over heating in at the drive though.

[dakon]

here is the build thread.
http://www.m42club.com/forums/showthread.php?t=12099


just got it home on friday, after driving from beaufort SC to atlanta approximately 300 miles, then from atlanta to dallas about 730 miles. during the entire trip the car had no issues with temp, it was dead in the middle of the temp gauge.


Today i took the car out to do some errands and ended up in the drive though as i was waiting, i noticed that the temp needle was almost pegged high in the red.

Turned the car off, and waited for my food... got the food, then went strait home, as i went home the temp gauge dropped from the red, to the upper 1/4 so it was cooling down.. when i got home again turned the car off immediately, and left the hood open to help the engine cool off the distance from the drive though to the house, was maybe 2 miles at the most..

i did not notice exactly when the temp started creeping up...

all of the temp sensors are new, as well as the thermostat and water pump.. the only thing i can think of right now is a bad fan clutch as that is not new...

later this week, i will take the car out, and get it up to temp, then bring it home, and let it idle to see what the temp gauge does, and verify if the fan is or is not coming on. however i do not think that the fan is coming on......



i will have to do some more googling, however if any of you guys have any input i would greatly appreciate it.


Thanks again.

[dakon]

bad fan clutch....

[dakon]

replaced the fan clutch today, still having random heating issues. while driving, the temp is reading 1/4. at a stop light, it will creep up to maybe 1/2. Then when you take off it drops back down... when parked in the drive way, it held at 1/2 for about a minute, then slowly started creeping to the red, took about a minute to go from the 1/2 to the bottom of the red. when it reached the bottom of the red i killed the motor..


with the new fan clutch, the fan is pulling a WHOLE lot more air.. however the aux fan never did kick on.. i was not running the ac at the time though....


any ideas?

Radiator, that is the only other part of the cooling system that is not new....

or could it be a bad gauge cluster not displaying the temp correctly? i will be doing more research, and would rather not just buy parts without knowing that they do need to be replaced.. if it needs a new radiator, i am ok with that, but don't want to just go out and buy one in hopes that is what it is.

just bled the system got some air out, also added some coolant. took the car around the block, then back to the drive way.. temp started to creep slightly, however this time at 3/4 i revved the motor to 2000 RPM, and the temp immediately dropped to 1/2 and stayed there for a little bit, then started creeping again.

any ideas?

Thanks for any help!

[monty23psk]

Well, I have done all the things possible to my cooling system on my m42, so I can help. The fact the it goes back down from 3/4 means the fan clutch is working. First thing to know, what is the outside temp of your area? Next, when the temp goes to 3/4, does it stop there or keeps creeping to the red, and I assume the only time it creeps is when the car is at idle or stop and go traffice, correct? We can take it from there.

[dakon]

fan clutch is new.

i am sure it would continue to creep up, i decided to stop it at 3/4  as i don't need to press my luck with an over heating condition.

these are the events of the day.


first
i jumpered the aux fan in both fast and slow, that did slow down the over heating condition, however it was still present. the aux fan hasn't kicked on, on its own, so i am thinking about semi permanently jumpering it in slow speed like a male-female electrical connector, with maybe a male on the black/green, and a female on the brown/black and black, so in the summer i can switch to fast speed if i so desire.



second
i bled the system 3 times today, and that seems to have helped now it sits at just over 1/2 and doesn't "seem" to be creeping anymore, at least not in the amount of time i was willing to wait, if anything it is MUCH MUCH slower now if any at all i also added about 4-6oz of coolant...


the ambient temperature is in the 60's.

at this point everything in the cooling system is brand new, if you look at the build thread you can see how in-depth we went with the build....


there was a VERY noticeable amount of air movement from the old fan clutch to the new one, so i know that was at least part of the problem.

the radiator is original, maybe it is partially clogged, there was some crap on the sides of the expansion tank.

[monty23psk]

Ok, the outside temp is ok, just making sure as not sure where you are located. But to give you an idea that you do have an issue, I live in Miami, FL, have replaced all the cooling componets, using stock thermostat and removed fan clutch. Just have an aftermarket SPAL fan in place of the aux fan. All my aux fan electronics work and when the car gets to a little past half, the fan turns on. But when I am driving and its over 80 degrees outside, my needle is just past a 1/4th, way before half. With city driving it stays at noon or a little past until I get moving. If it is bad traffic and a lot of stop and go, my needle goes past half and as it gets to 3/4, the fan turns on to high and by itself cools the engine back to half. If I have my AC on, the fan is on low and everything I just describes takes even longer. So if you have a fan clutch and your are getting the temp up, I think you have still air in system, or somewhat of a blockage. When the needles gets past the half mark, especially closer to the 3/4 mark, is the hose on the passenger side going to the radiator getting hot? If not, the t-stat is stuck closed. Also, you might want to give a good flush of the block and radiator. Sorry I have not followed your build, so not sure what you are doing. Also these cars take littel coolant, a total of about 2 gallons, so 1 part water, other coolant. My heater does not work, but if your does, make sure it is on, to circulate coolant through heater core.

[318lotis]

when you bled system, did you elevate the front end?

also, sometimes i can gently tap the top of dash over temp gauge and needle will will correct itself.

[dakon]

the driveway is at about a 5-10 degree incline, so yes the front end was slightly elevated.

i need to get a second person to help verify the aux fan issue i know for a fact it works in both speeds but i am not sure it is being actuated by the temp switch, and i dont want the temp to be around 3/4 and rising while i am looking at a fan...

[monty23psk]

if you jump the temp switch and it works in both high and low, then you aux fan and resistor are fine. You might replace the temp switch anyways since it might be original. You can test it in boiling water, at least the low side. Very hard to get water up to 99 degrees. Also if your fan works on low, or with the ac on, your diode is fine. Mine actually went bad as its located in the fuse box. So looks like it is just the switch.

Did you check the other hose I was talking about or when was last time you did a flush, both blok and radiator. Lastly, your radiator might have to much debris and is shot. That happened to mine and got a new one. I took it to a radiator place to have it tested.

[dakon]

the temp switch is brand new, i need to verify the aux fan works with the ac on, i'm pretty sure that it does... at this point i am thinking 1 of 3 things are possible.

1) possibly a small amount more air in the system, due to the fact that i got some air out when i bled the system yesterday....
2) partially clogged 20 year old radiator..
3) some combination of the 2 above.

at 65 degree ambient temperature there should be absolutely no reason that the car would require the aux fan, the main cooling fan is pulling a crap load of air though the radiator.. the plan is to get this fixed during winter break, if i am having cooling issues in 65 degree weather, what will the 3 months of 100+ degree weather be like.... eek!

i have not checked to feel the temp of the hot side hose yet. i will do that, however i am pretty sure that the thermostat is working properly because

1) its brand new, and the premium thermostat (granted even a new part can not work properly)
2) if i was having a thermostat, or water pump problem, i would not have been able to drive 1000 miles with 0 cooling issues..

with a radiator with a reduced cooling efficiency, that would explain why i did not have any problems at highway speed (70-90), but do have problems at idle..



monty, when you took your radiator to get tested, did they test the cooling efficiency of the radiator, or hydro it/ and flow-rate measure? how did they test the radiator, and how much did it cost if you don't mind my asking?

i don't mind buying a new one, as bav sell OEM ones for 200 bucks, however i would like to get a performance aluminum one with a aluminum expansion tank, rather than the plastic design, however i am not willing to pay triple the cost for an aluminum one, where did you get your new radiator from?


thanks again for the help

[monty23psk]

yes I am guessing a combo of 1 and 2 you listed is happening. Actually if you have the thermostat working, you have another coolant passage, which yes, can give you better cooling but also have another area with air. If it is not working, then you have hot coolant going back to the other hot coolant. Just need to verify that hose is getting hot.

Regarding the radiator, I believe it was a flow-rate measure, but right at the beginning gunk was coming out. So he said he stopped and gave it back to me. He didn't charge me, but believe it would have been about $50 bucks to test. I wasn't there for the test, just called my phone when he found out.

I got my new Behr one on ebay and paid about $180. Just be careful for the knockoffs. I too would like the aluminum one, but will wait until this one dies before even contemplating that. I dont have a fan clutch and have excellent cooling, which might get me 1 hp also, and better gas mileage. Eventually will do the same with power steering.
Anytime.

[rjcaptsean]

So what was the verdict?