Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: dakman29 on August 24, 2014, 20:04:43
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Hello: The radiator on my 68 280sl is leaking badly at the lower tank. Trying to decide whether the high efficiency record advertised on Gernold's site is a worthwhile fix or should I just have a standard record done locally. I'm on the west coast so shipping the radiator to him and back won't be cheap. Any thoughts? Thanks.
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No doubt others will have a different view, but a recore is a recore. Unless one increases the capacity of the radiator then only a finite amount of coolant can be cooled, and that limit is set by the size of the radiator. Increase that size and you get more cooling.
And anyway, if you don't have an over-heating problem, why go to the expense of shipping the rad across the country?
I'd find a good local place that you can have a dialogue with. I had mine record 6 years ago and it's been great since. Nothing fancy; just good old-fashioned (eye-wateringly expensive) German craftsmanship.
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I got mine redone here in NZ, in the small town I live in, about 2 years ago. Very pleased with the results. The local radiator shop was able to locate the correct core in NZ.
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.... Unless one increases the capacity of the radiator then only a finite amount of coolant can be cooled, and that limit is set by the size of the radiator. .....
Aahh .. looks like we need a bit of physics here. ;)
Yes, the amount of coolant that needs to be cooled is constant and the size of the radiator determines how much heat can be transferred to the surrounding air.
But the speed by which this can be done is not determined by the "size" but by the surface of the radiator and that is what changes in a "high efficiency" recore, the more copper lamellae (or fins) the larger the surface area.
Still, that is not all that goes into the equation, one also needs to take the air flow into consideration. It is easy to increase the surface area - one could just use a copper sponge - but that would not help because the air can't be moved fast enough through the sponge. Thus a larger surface area recore will only bring an advantage as long as sufficient air is moved past the fins. At high driving speeds that is not a problem but when you are standing still in traffic at 37ºC ambient temperature you better hope your radiator fan moves enough air. Better to use one with 5 or 6-blades than 4.
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In my case the thermostat housing is not in best shape and I may source a new one to replace the one now on the car. When my car was last at the Benz Dr. we had problems sealing the joints, Dan managed to do it in the end. Still the joint face is in very poor shape and it warrants replacement or repair perhaps with devcon (plastic metal filler) and re-machining the joint??? Perhaps the best solution is a new housing?
I'm just wondering if the OP has checked the exact location of the leak, the joint face of the thermostat housingh is certainly a place to have a close look at.
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I just went to a local rad shop to get mine recored 2 years ago. Just phone around and ask them what they do and how they do it. Most rad shops will also repaint them but I didn't as I wanted to see the welding before it got painted. I also had them install 3 cores instead of the two that were originally inside the rad. Didn't change the thickness of the rad and the engine runs at a steady 80-82C now. Very happy with the improved cooling. While you have the rad out it is a good time to replace belts and the water pump if it hasn't already been done.
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No doubt others will have a different view, but a recore is a recore.
Not so. Typically here in the USA today, a "recore" involves removing the upper and lower tanks, and then buying stock "cores" from the people who make them, or distributors, then soldering it all back together. Which cores does the shop use? Are they all the right size?
The story I heard from Gernold (SL-Tech) was that he tried to find someone who would work to his specification, but doing so with stock cores was not possible. So, he found a guy who actually had the equipment to make the cores, and the re-cored radiators from SL-Tech are custom made; not stock cores. Pricey? sure. Old world craftsmanship.
For what its worth, I had a recored radiator from the start on my car since the restoration, and it always ran hot, and in conditions that Albert described, stop and go at 37c with little air flow, was always on the hairy edge of overheating. I bit the bullet in 2011 and bought a recored rad from Gernold, and it has never run cooler. Much improved over the old recored unit, which was 3-row. Others have reported similar results, while some have no problem with any old re-core from any shop. I'm just happy I have something that works.
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There is two parts to the radiator recore saga.
You can just remove and replace your radiator, and you should get some improvement in cooling, or as Michael/Alfred said get one with greater surface area, but with out properly flushing the water lines through out your engine, and whilst you are at it replace the water pump, you are only doing half the job and unlikely to be really successful in managing the ‘whole’ cooling system. It is a combination of surface area and water flow through the system combined that equate to the amount of cooling that can be achieved.
Many fall in to the trap of just replacing the radiator and then wonder why they still have some over heating problems when they have not done a proper chemical flush of the whole system, nor replaced their water pump which probably has a corroded impeller that is also reducing the water flow as well..
My pennys worth.
Garry
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I was going to add that you should replace the water pump (and banjo bolt) at the same time. Garry beat me it it.
It's good advice, not remotely hard, and relatively cheap.
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A couple of years ago I had a 230 that was overheating.
Naturally we ensure that every part of the cooling system is in order before concluding that a new radiator was required. I fitted a second hand radiator that I had lying around and the overheating problem was gone. I sent the original radiator for re-core and then re-installed it; overheating returned! I removed the rad again and sent it back to the rebuilders asking them to check it. No fault found. I asked them to put in a high efficiency core and then re-installed the rad. Overheating problem persisted. I re-installed the second hand rad; problem cured!
I ended up having to leave the second hand radiator in the car and still have that re-cored radiator waiting to be tried in another car.
Weird.
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Here's a shot I took of a Pagoda radiator being tested for flow ... The flow was quite weak in the center part as you can see from the photo --- ended up doing a re-core.
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In my case the thermostat housing is not in best shape and I may source a new one to replace the one now on the car. When my car was last at the Benz Dr. we had problems sealing the joints, Dan managed to do it in the end. Still the joint face is in very poor shape and it warrants replacement or repair perhaps with devcon (plastic metal filler) and re-machining the joint??? Perhaps the best solution is a new housing?
I'm just wondering if the OP has checked the exact location of the leak, the joint face of the thermostat housingh is certainly a place to have a close look at.
I found that my housing cover was quite pitted and I replaced it last year with one from the Classic Center. $55 if I recall correctly.
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Thanks to all for the responses. I am going to speak with the local shop to see if they can add a third row of tubes/fins. I've not had overheating issues with the car so I think that if all they can do is a standard recore, then I'll probably go that route.
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First of all ... Great Tread!!!
Here is my situation, My radiator is leaking now and has been in the past. First it became evident when Dan (Benz Dr.) replaced my fan clutch when we put things back together in his shop coolant was leaking when i pointed out that the leak is from the horizontal joint of the thermostat housing. Dan's people managed to seal that leak somehow. Now I do have a leak at the bottom area of the radiator.
My plan is to change the radiator (like Michael did get a new one from Gernold) and arrange to change the water pump and belts at the same time since the hood has to come off and with the radiator out of the place it can all be done in one wash. At the same time I'm thinking to replace or repair the thermostat housing. It would be a nice winter project. I will do some research as to the aforementioned replacement parts.
BTW I asked our friendly Mercedes Dealership (near my home) to give me a quotation for the work ... it be interesting to see what price for parts and labour they come up with. :)
Any thoughts ... is my plan logical or not?
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R-D, you do not have to remove the hood to get the rad out. You can raise the front end and take it out the bottom. There are several threads describing it if you do a search.
dakman, you should be able to add a 3rd core without changing the original dimensions of the rad. If your rad shop says they can't then I would talk to a different rad shop.
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Thanks Jordan, I think I will have a good flush done at the same time, so it will be done at a shop. May aswell do a 100% job when all is apart including some new hoses.
Did you have your rad re-done or did you get a new one?
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Jordan is right! But it sounds like you really want to do all that stuff and you have more extra money than I do... :o They didn't tell you what was wrong and what they did to fix the thermostat leak? And now, you are concerned that their fix was not professional, (permanent as opposed to temporary)?? I'm confused.
There isn't much there but an O-ring. If it wasn't a metal corrosion or crack thing, all they did was replace the o-ring. If that is the case, problem solved, permanently, professionally. Atleast until you need a new o-ring or thermostat, 10 years from now. Call them and ask what the problem was.
With a leak from your radiator and not just a hose, you have no choice but to drop the radiator. Make sure its not one of the hose or hose clamps. I would never pull the radiator: you have to remove and replace the hood. The hood is custom fit to your engine bay, with a crazy technical tortion bar spring that you don't want to mess with if you are skiddish about a thermostat housing. It takes an artist with a minor in mechanical engineering to get it back in there.
I just had a local 3 row high efficiency re-core. Cost $425 due to the high cost of brass and copper. It is supposed to have little fins in the tubes... What is a new one $850? The local $425 rebuild radiator works fine and is new except for the top and bottom caps. The actual radiator part is all new. Comes out the bottom and with the radiator and fan out you get to the front of the motor from below.
Great picture of the flow test!
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R-D, I used my existing rad and replaced the 2 row core with a 3 row, as Gary describes. As he says, only the top and bottom caps are retained, the fins get discarded for new ones. Two years ago it was $400 to have the rad recored, welded/soldered and pressure tested. I did not have it repainted, I did that myself.
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Thank you both Gary & Jordan!
Gary, the problem with the thermostat housing was corrosion very bad indeed. I will make sure it is the rd and not the hoses or clamps.
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Dieter,
As I did this myself it was about a 10 day project, merely because there are so many items to remove, and I elected to have the bulk of them powder coated. So, the fan shroud, air cleaner components, fan itself, etc. were all sent out.
I would suggest replacing the water pump too, and pay particular attention to the "long/short" issue on that. You probably have a short pump and want a long pump.
Obviously you want to change that cracked housing, and probably some hoses and belts while you have it all apart.
All doable from beneath the car, slow and steady.
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I also had issues with the radiator. 3 row recore did the job. Cost: 240 euro
No more overheating problems since then.
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Thanks for the heads up Kevin, I will order one and have it on hand.
Thanks Michael, I will tackle the project on my own (after all that is part of the reason I purchased this car to keep me out of mischief LOL), I purchased 2 ramps last fall since I needed access from below to install a missing part after I had the fan clutch changed. I guess my long trip to Williamsburg, Virginia last September brought the radiator to it's well deserved final rest :) Looks like the original to me. A local shop here in London, Ontario that does mostly radiator work will re-core it for me for $400- once I got her out.
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You might ask them if they will "Rod It Out" They do much the same work, so the labor is similar, but you don't have to pay for a new core. They flow test the core, and gently run stiff rods of incremental size through each tube. I would think some old Brits would be familiar with saving a radiator this way. Of couse, it is more profitable and a much cleaner proceedure to order a replacement core, charge you double, and have an easy time soldering the three parts back togeather.
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Fruit for thought ....
I've been thinking back to last week when the fellow pulled my car in neutral up to his flatbed truck, he used the tow hook on my car (on the driver side front) I made sure it did not touch the radiator when he pulled the car up. However, once the car was up on the truck or even during the removal of the car into the shop (he backed right into the shop to unload) it may have made contact with the radiator. I say this since ...
A) The radiator was fine before the car gave up on me on the highway (also no evidence in my garage of a leak).
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B) the leak is right over the tow hook on my radiator.
To late now, I have to pay the piper to fix it, I just pass this on to you fellows to keep a sharp eye out during the entire operation(s) of getting the car up and back down from a flatbed should you ever be faced with that situation.
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R-D, if you are going to remove the rad yourself, make sure you pay attention to how far away the fan blades are from the fins on the rad. I don't have a shroud so it was important in my case. I took lots of measurements before I removed my rad so it went back in the same spot. The rad has some play once you start loosening the screws on the sides so you want to make sure you put it back in exactly the same spot. There are also thin strips of rubber on the sides of the rad to prevent it from rubbing up against the bracket. You will want to replace these as well no doubt if they have never been removed before now.
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So the radiator recore is done. The radiator shop installed a core with higher capacity tubes and the cooling system is functioning perfectly. I told the shop that diagnosed the problem that I wanted the radiator removed out the bottom of the car so the hood (bonnet) did not need to be removed. They said they had not done it that way before but they would try. First I got a call from them saying it looked like they could take it out that way. The next call I got was after they had removed the rad. from the top of the engine bay (hood removed). They said that they couldn't break the oil cooler loose easily and didn't want to damage anything so they took it out the top. When they called to say the rad. had been re-installed and I could pick up the car they said, but . . . when reinstalling the hood, one of the four nuts attached to the inside of the hood to receive the mounting bolt had broken free and dropped down inside the unaccessible space in the hood. They tried to fish it out but could not. They remounted the hood with three bolts and it is functioning seemingly fine. Obviously it was designed to have four bolts in place. So, first question is how quickly do I need to find a solution for the problem, meaning do I risk damaging the hood by raising and lowering it with a missing bolt. Next question is what is the recommended fix, and finally, how shady or perhaps dishonest is the shop. I say that because when I picked up the car I asked them to show me what had prevented them dropping the rad. out the bottom. Guy pointed to the large nut fastening the oil cooler line to the oil cooler and said it couldn't be broken free. It didn't occur to me at the time, but later I started thinking that if that was the case, how did they get the rad. out of the car at all. I'm going to go back to the shop on Monday with my concerns but was hoping for some thoughts from the forum before doing so. Thanks.
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Reinstallation of my radiator was completed last Thursday after re-core. A radiator shop in our little town that also handles race and track cars did a fine job $403 to re-core plus plus antifreeze $24- and tax all is well again with my Blue Tornado :)
No problems encountered removing it from the bottom or re-installing it. Thanks Mike for your guidance.
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Hi Rolf,
Just wondering if your going to do your thermostat at the same time for good measure.
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Easy to test it. No point throwing away good money without testing it first. Requires kettle plus thermometer and a thermostat. I still have the replacement one I bought to change it when some bright spark suggested I test the original. Worked fine.
My spare is for sale.... ;D
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James are you running a 79 or 87 degree thermostat. I just replaced mine and am a bit worried that the new one is 87. I suppose in hotter countries the lower one is the go. The thing is I dont know if little old New Zealand fits into this category.
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No Andy, I am leaving well enough for now alone. The joint of the housing was leaking due to erosion when we changed the thermostat and the fan clutch last year. The Benz Dr. (Dan) and his boys fixed it and so far it is not leaking, however I keep my eye on it :)
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dakman29, not sure about the oil cooler line. I have a 230SL so thought maybe it might be different since you have a 280SL, but RD also has a 280SL and he got his rad out the bottom. Perhaps the shop you used was just too lazy to raise the car up enough to slip the rad out the bottom. Regardless, they should supply and install the 4th bolt if they are the ones that removed and lost it. You should get the car back in the same condition you left it with them, except for the rad repairs of course. Just my 2c.
BTW, don't know about others but I can tell my thermostat is working when I start the car cold and start driving it. The temp gauge will climb to just above 80C and then I can see it drop back as I continue driving. Takes maybe 5 minutes of driving to see it drop back. I am assuming this is the point at which the thermostat opens.
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Regarding the 4th bolt in the the hood - there is lots of discussion on the site about that 4th bolt - the captive nut breaks free and the solution is to cut a hole beside the hole in the hood and slide a threaded metal plate in there to replicate the captive nut - there is added tension on the single bolt on the one side - you be the judge - 1 bolt holding your hood down or two?
I don't know of any easy fixes without cutting up your hood - anyone else ever find a way of securing the hood without a captive nut to attach to?
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There are very few cars out there with hoods that open "backwards" Radiator guys are not usually the sharpest knives in the block! I seriously dought the even tried not to take the hood off. And once they got started, there was to turning back. They could have broken the captive nut off going or coming. It is kept in aluminum! Should I say again, very few cars out there are made of aluminum!!! And radiator guys.....
I don't know about you, but I open my hood a lot. Very frequently! The hood is raised with one hand on one side and the coun ter spring is under very high tension. Those two little joints supporting the hood hinges are, I would say 'a bit delicate' Have the idiots repair your hood, emmidiately. If they refuse, take it to a good body shop and pay the body shop then sue the ham hands in small claims court. I seriously doubt they got you hood back in there right. Sorry.
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... Next question is what is the recommended fix, and finally, how shady or perhaps dishonest is the shop. ...
Dakman,
you should get it fixed, but I would not trust a radiator guy to do it correctly, certainly not that crew.
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Good point. My assumption was they would refuse. The risk is they will screw it up some more.
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Thanks for the suggestions. I am an attorney and fully versed in the remedies that the law may provide. I guess if I were an engineer I could figure these mechanical questions out for myself. First I should explain that there are two shops involved. The foreign car independent shop diagnosed the problem and were the ones who removed the rad. They then sent it out for the recore. The rad shop is blameless here. I went to the independent shop this morning and explained that I couldn't understand their explanation for not dropping the rad from the bottom, as the oil cooler connection would have to be split either way. They said that they couldn't get enough leverage on the fitting with the hood in place. Still sounded a bit fishy. I represent a number of new car dealers in town with body shops and probably won't get hit too hard on repairing the dropped nut. The indy shop agreed to remove and reinstall the hood without charge so a body shop can undertake the fix. That sounded fair. On that point I checked Gernold's website and saw the picture of the plates with the sandwiched nuts for this repair. Unfortunately they are out of stock. I called to find out when they may be available. Gernold said that they won't because his German supplier isn't making them any longer. So we'll have to find some other way to secure the last bolt. Gernold felt that the existing part could be repaired by cutting an access hole, removing the two rivets and reinstalling the captive nuts as from the factory. So I guess we'll see. Of course if anyone out there has one of Gernold's plates and is willing to part with it, please let me know. Thanks again for all your help.
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Sounds like you have it covered well. Maybe we should add you to our list of resources!
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You should be able to make one of these plates fairly easy with a flat piece of steel. Simply cut to a suitable size and drill and tap it with the appropriate size metric tap. I had to do this on my hood several years age. I did have to cut a small access hole on the side using a Dremel rotary tool with a small abrasive disk. When the hinge is installed it totally covers the access hole.
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"Sounds like you have it covered well. Maybe we should add you to our list of resources!"
Always happy to try and help a member with an automotive related legal question. Don
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Hello dakman29,
I hope you resolved all your issues with your radiator. Just an update, there is absolutely no need to remove the hood in order to slip out the radiator. You can confirm this by stoping at a good radiator shop that do this kind of work all the time. If they tell you (in future of course) the hood has to come off I recommend to get into the car and drive away and find the next shop. Removing the radiator from the bottom was no issue for me (I used 2 ramps - see photo). At the same time I cleaned and painted my oil cooler. All went well.