I'll pick one up tomorrow or Friday. Checked the timing and it was retarded 10 degrees. Set it at zero and drove it around for an hour. Drove it in stop and go traffic around noon and it did get hot but didn't overheat. Temp gage went to just under 120 and I stopped to check with an infrared thermometer, which read 107. Temp at bottom of radiator read around 55. Keep striking out on getting citric acid so I'll just buy some online. I'll pressure test the cooling system tomorrow.
ethanol or even water-only mist system will help in a huge wayI have a 1981 380SL and swapped a 500 SEC engine into it. Still trying to work the bugs out of it but it keeps overheating. Here in L.A. it's been hot and traffic is bad. I can drive it for 30 to 45 minutes and the temp slowly creeps up. Once it gets to 120, it wants to stay there. The water pump and thermostat are from the 380. They're both about 3 or 4 years old but only have a few hundred miles on them and worked fine in the other engine. New radiator cap and expansion tank. I'm going to look into getting a bigger core for the radiator tomorrow but wanted to know if anyone knows of other radiators that would fit and solve my problem.
It might be interesting to compare the core sizes of the original 380SL (or your new upgrade) with the rad that the 500SEC would have used. Better still, compare it with a 500 or 560 SL rad that would have had to fit in the same SL space.I'm going to look into getting a bigger core for the radiator tomorrow but wanted to know if anyone knows of other radiators that would fit and solve my problem.
Sorry, I know you are trying everything - just throwing these out because they cam to mind.The classic symptoms of too much backpressure include things like a lack of high speed power, poor fuel economy and even overheating. Anything that backs up exhaust pressure into the engine will also back up heat. About a third of the heat produced by combustion goes out the tailpipe as waste heat, so if the heat can't escape it can overload the cooling system and make the engine run hotter than normal, especially at highway speeds
I appreciate all help. I can find the area of the 560Sl and 500 SEC radiators but not the volume. The 500 SEC engine puts out 18% more horsepower. I'll have to check the specs on the exhausts, didn't think of that. However, it's not running hot at highway speeds. It goes down to around 100 degrees at highway speeds. The exhaust is also louder with this engine, which leads me to believe it's not that restrictive. I got the 75 degree thermostat today. It's a Stant and Stant says that the engine should run around 95 degrees with this fully opened (I know, this would be if everything else were perfect). Ordered Citric Acid today. Pressure testing the cooling system tomorrow. I met and talked to an old school MB mechanic today. He told me to test the fan clutch by trying to stop it with the engine running over 100 degrees and the electric fan on. Couldn't stop it so, according to this guy, the fan clutch is good. I feel that I'm going in the right direction, since I was able to drive the car today without it overheating.It might be interesting to compare the core sizes of the original 380SL (or your new upgrade) with the rad that the 500SEC would have used. Better still, compare it with a 500 or 560 SL rad that would have had to fit in the same SL space.
The 500SEC engine could have had something like 50% more horsepower than the 380SL? If so, that would also mean that there would be about 50% more waste heat to dissipate. That would presumably require about 50% more heat transfer area in the radiator. Of course, the 380SL rad may have been oversized so maybe the rad does not have to be 50% bigger.
One other thought - how does the exhaust system compare with a 500SEC/500SL? That is the other way heat gets removed? Would a restricted exhaust cause overheating? Seems so according to aa1car.com :
Sorry, I know you are trying everything - just throwing these out because they cam to mind.
Are you talking about the aux pump or the older ACC 2 climate control system?I pressure tested the system today. Had to tighten a couple of hose clamps. Also appears that the heater control servo is leaking. Crap! Tightened all the hose clamps but no luck. There appears to be a seam above the hose fittings and it looks like that might be the source of the leak but I'll have to take it out to be sure. This is disappointing.
It's the ACC ll. I've never noticed it leaking before. Right now, I'm going to do the Tide and citric acis flushes and go from there. I'll replace it with one from Mercedes Fix when the time comes. I've been spending so much money on this thing lately that I don't want to deal with it right now.Are you talking about the aux pump or the older ACC 2 climate control system?
If it's the aux pump, you can safely remove him from the system. He's a useless appendage. Find an L pipe and drop it in.
Also, make sure to remove the Schrader valves on the harbor freight kit. They cause erratic pressure readings.
Yes, a myth that defies all the laws of thermodynamics.That's one of those urban myths that just ain't so. However, running without a thermostat creates the problem of too much cooling, preventing the engine from reaching full operating temperature.
I'm not finding anything with this Google search. Is it spelled correctly?Find your proper timing spec for the engine (m117?). Set that first, once you've done that, Google myndex's kjet dianogstic diys. Really easy to do.
This is assuming you still have the the old fuel ECU components.
You might not pass smog with this though. I'd get ready for a visit to a smog referee to have them modify your smog requirements for the engine changeover.
Not the end of the world since you still have the old smog components and plumbing.
Don't know which law of thermodynamics would apply to running without a thermostat in a Mercedes? Might be some other kind of lawYes, a myth that defies all the laws of thermodynamics.
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I'm not finding anything with this Google search. Is it spelled correctly?
Sorry but I misunderstood what you were trying to tell me earlier. I've seen this and bookmarked it. I even bought an oscilloscope last month. Took the car out for another drive. This time I took the infrared thermometer and checked the temp when the gage was at its' highest. Temp was 95.Well, the last few days have been quite interesting with what I have learned/discovered about K-Jetronic with Lambda systems. I set out with the goal of getting the mixture right on my 1980 450SLand did so by attempting to use a duty cycle meter… only to discover that it is NOT possible! A lot...www.benzworld.org
95 is great! My 380 hovers between 85-95 depending on AC usage. I think you might be towards the end of your tunnel.Sorry but I misunderstood what you were trying to tell me earlier. I've seen this and bookmarked it. I even bought an oscilloscope last month. Took the car out for another drive. This time I took the infrared thermometer and checked the temp when the gage was at its' highest. Temp was 95.
How much citric acid did you use? I did some calculations last week and came up with needing around 40 ounces. I'm just not sure when calculating a solid into a liquid.Mirv,
Consider a detergent flush followed by a citric acid flush - I was shocked how much gunk came out when I did this. Also consider a radiator recore with more tubes for more heat capacity since your displacement has increased. Finally, evaluate the health of your visco fan.
None of this is easy or cheap - I fought it for 4 years.
It's a lot easier in metric! Density of water is 1gm/cc or 1000g/1000cc (liter). Shop manual says to use 10% citric acid. So you add 100gm per 1000gm of water (1 liter). (100gm=3.527 oz)How much citric acid did you use? I did some calculations last week and came up with needing around 40 ounces. I'm just not sure when calculating a solid into a liquid.