Man, the heat is exposing some new issues with my 1992 400E. One is the electric twin fans don't seem to be working. Should they come on even with the hood open? I seen another post dedicated to troubleshooting this issue on this site. I'll try and find some time to tackle it.
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twin electric fans
- Thread starter jgt157
- Start date
I was finally able to check out the fans and they do work. I found a bare wire on the connection between the a/c refrigerant temperature switch. Fixed it and the fans now come on when the a/c is on. But, the coolant temperature still creeps up to over 100 when the a/c is on. Any ideas why? It stays between 80 and 100 when the a/c is not in use.
How far over 100C? On a hot day with AC on, it might go a bit above 100, say a needle width or two, ~105C. That's nothing to lose sleep over. You'd have to do quite a bit of additional diagnostics to determine if the temps could be reduced a bit.
It was about 77 degrees outside yesterday when it went over 100. I was afraid to let it go any further. When I shut the air off the temp slowly drifted back to approximately 90. Any recommendations on what to start checking. I'm at a loss since the temp is pretty stable without using the air at about 90 and the fans seem to be working.
So 10c - 12c is too much. I'm going to try and pressure wash (on low setting) the radiator fins. I did a tissue test when the twin fans were on and there didn't seem to be much air being pulled in through the radiator (not as much as I would expect). I'm not seeing any oil in the water or water in the oil so that's ok. The only things that would be left after that (that I know of) is the water pump, the thermostat and the radiator. I'm not thinking it's the thermostat. That leaves the radiator and the water pump.
Two years ago, I installed a new Nissens radiator in my car due to failure of the original unit.
Two weekends ago, as part of the process of replacing the fan clutch on my car, I had to remove the radiator (again) so as to get a better angle & more room to remove the "stuck" 8mm fan clutch bolt.
I found that in just two years, and probably 10,000 miles, there was a significant amount of "crap" that had accumulated in the lower portion of the radiator fins. I used a brush and removed it once I had the radiator out of the car. I don't think it was affecting cooling efficiency, because nothing was absolutely blocked, but there is definite possibility that for a radiator that hasn't been removed and cleaned, that there is diminished cooling capacity due to collection of crud at the bottom portion of the radiator.
It's about a 30-minute job to remove the radiator and same to replace it. Not too difficult a job -- biggest pain is draining the thing !!
Thermostat is a good proactive replacement, particularly if it's never been documented as being done. I did this job earlier this year and have a HOW-TO on it. Good opportunity to replace cooling hoses in the area, as well.
Cheers,
Gerry
Two weekends ago, as part of the process of replacing the fan clutch on my car, I had to remove the radiator (again) so as to get a better angle & more room to remove the "stuck" 8mm fan clutch bolt.
I found that in just two years, and probably 10,000 miles, there was a significant amount of "crap" that had accumulated in the lower portion of the radiator fins. I used a brush and removed it once I had the radiator out of the car. I don't think it was affecting cooling efficiency, because nothing was absolutely blocked, but there is definite possibility that for a radiator that hasn't been removed and cleaned, that there is diminished cooling capacity due to collection of crud at the bottom portion of the radiator.
It's about a 30-minute job to remove the radiator and same to replace it. Not too difficult a job -- biggest pain is draining the thing !!
Thermostat is a good proactive replacement, particularly if it's never been documented as being done. I did this job earlier this year and have a HOW-TO on it. Good opportunity to replace cooling hoses in the area, as well.
Cheers,
Gerry
Both the radiator AND condenser fins have to be cleaned out. You need compressed air to do this properly, and have to blow from the back to the front (at least at first). A shocking amount of debris is trapped in there. If the radiator is original, it would be a good idea to replace it proactively after 20+ years.
Again, temps up to ~115C are not dangerous... no need to turn off AC and/or turn on heater until you are near 120C. The electric fans will turn on high speed at 107C. My one 500E has new everything (radiator, fan clutch, t-stat, pump, etc) and still runs 100-105C on a hot summer day with AC on. My others run a bit cooler but I've stopped worrying about it.
Again, temps up to ~115C are not dangerous... no need to turn off AC and/or turn on heater until you are near 120C. The electric fans will turn on high speed at 107C. My one 500E has new everything (radiator, fan clutch, t-stat, pump, etc) and still runs 100-105C on a hot summer day with AC on. My others run a bit cooler but I've stopped worrying about it.
Do any of you use the same condenser coil cleaner/degreaser that's used on home A/C units ? I have some extra which is non-acid base (alkli) and I was thinking about using it after blowing out all the crud.
Makes a BIG difference on my heat-pump condenser hear in Jax, FL . . .
neil
Makes a BIG difference on my heat-pump condenser hear in Jax, FL . . .
neil
I used some home A/C foaming evaporator cleaner on my 87 300D, but don't think I ever used cleaners on the condenser. Can't think of a reason why you wouldn't want to use alkali cleaner on the condenser, as long as it doesn't damage paint.
