Runnin Warm In Heavy Traffic

[BerkeleyChemist]

Over the last few weeks I got caught in real slow San Fran traffic <5mph crawl. The temp hit the bottom side of the hot yellow mark. I have had this car a year and this is the only recent cooling issue. With 125K currently...it had a new water pump and radiator in at 85k, next was the top hose replacement, temp switch, fan relay and new coolant in at 120K. I think I bleed the system sufficiently. The fans work, at least they turn on. They maybe weak sauce. I have the exhaust wrapped up to up to the converter to help with the heat issue. I know it leaks coolant at a rate of 8-12 oz per month. Not all the hoses have been replaced though. The bottom one or block off is leaky.

My next task will be to replace the remaining hoses, even the heater core hoses and valve, all clamps, the reservoir tank, the pressure cap w/ anode, block off and seals. Replace the thermostat and considering changing to a lower temp for the thermo or the switch in the radiator to lower. A lower temp switch could act as a feedforward control in this situation, but may cause electrical drain when most of the time is not needed. The hose and tank replacements are a must for a few reasons.

1)they dont burst
2)they dont flake up and clog heat exchangers
3)they dont leak

After I piece it together, I am taking it to get pressure tested. Does a leak really jurt the system? I fear it could get an air bubble in there and stop my waterflow.

I guess I could direct wire in a switch to turn on fans, possibly Binford model 100amp draw super coool deluxe, arr arr arr. Or have Tool Man Taylor re-spool them so they push harder. And at 200bucks each, this might not be a bad approach. Just remember high current = hot ass wires.

For real, Porsche makes good cars, most not watercooled, and 944's seem to have issues in this area. It might be weak airflow or something else wrong here. It might be this car isn't made for stop n go traffic jams.

The temp sensor for the gauge comes from the top of the manifold or head. If I can start moving in regular city speeds of 20mph, its fine. The harsh city traffic or interstate backups due to accidents make me nervous I am gonna smoke this old car formerly owned my an HP exec that maybe facing jail time.

Anyone care to provide input?

And please, no hot air, I have enough

[Razorback1980]

Did you buy the car from Patricia Dunn? I used to work at HP but retired in October. She was in a lot of trouble along with our chief legal person but I don't remember her name. Patricia was the Board of Directors Chairperson and was caught doing illegal wire tapping on people that worked at HP...so former HP exec in a lot of trouble.

Now for the over heating problem. First, confirm that both fans work properly and my car has always climbed a little during stop and go traffic so don't panic if it does that. The fans don't move as much air through the radiator as going 60mph does. I think replacing all old rubber hoses is a good idea but that is probably not causing your overheating problem. There are numerous posts on how to bleed the air out of the cooling system but it sounds like you have already done that but look up those posts as it might be educational. The last thing to check is whether the gauge is actually working properly. I would go pick up a thermal heat sensor or a thermometer so you can read the actual temperature of the engine. There are many grounds on your car and they can get corroded and that causes the gauges not to give the proper readings. The one for the gauges is somewhere under the dash but I don't know where for sure. PM a guy called JivenJim, I'm pretty sure he will know as he has done a lot of work on his instrument clusters.

I have two other tips to help....1. Don't drive your car like the one in the picture. Sure, running it over the cliff like that increases the air circulation through the radiator as it falls straight down, but it does lower the life expectancy of your car and you. 2. Don't let Tim touch your car...he is a muscle car dude and well, you have seen his show haven't you?

[Techno Duck]

Tom, i think letting the front end hang over the side like that allows for a nice updraft to help cool the engine.

Here is a nice guide to make sure everything in your cooling system is working up to par..in particular the fans.

http://www.clarks-garage.com/shop-manual/cool-01.htm

[SolReaver]

What coolant, h20, and ratio are you using?

[Razorback1980]

Tried that once when I was 17 only my car didn't stop. I can safely say that I didn't notice the engine temperature being high though!

Good point SolReaver..if you coolant mixture is over 50 percent antifreeze, then that will keep it from cooling as well.

[SolReaver]

Thx, RB, I learned that lesson on an Alpha. I needed an old school hygrometer to tweak the ratio before it stopped complaining. It was also particular about brands. Although there is not much chance a chemist is running Cheap Phosphate stuff with tapwater, it is good to rule it out and previous posts cover just about eveything else.

[Panzer909]

Originally posted by BerkeleyChemist


For real, Porsche makes good cars, most not watercooled, and 944's seem to have issues in this area. It might be weak airflow or something else wrong here. It might be this car isn't made for stop n go traffic jams.

If everything is working as it should, these cars can sit all day in CA traffic jams.......its yours in particular that has the issue.

Sounds like you're tracking down & eliminating problems. If it does have even a small leak and you are topping it off, its the air that will accumulate over time and run the temp up. Could also be a bad thermostat - this is an easy fix with the right pair of angled snap-ring pliers. Worst case is its a faulty waterpump even though it has relatively low milage.

My uncle's 944 had a similar problem. He ended up replacing almost everything related to the cooling system until he found the cause: a faulty temp guage. Go figure.

The beauty of these cars is that there is a logical cause and repair for every problem. You came to the right place.

[swimmingly]

I used to have issues with my car's coolant temperature going into the red in the dash gauge. The fans would kick on and seem to put a large load on the electrical system. Overall, I did not feel comfortable driving in traffic, stopping at lights on hot days, or driving uphill for an extended period of time.

I feel the biggest difference in coolant temperatures came when I replaced three sensors:
DME temp sensor
The other coolant temperature sensor on the block
Coolant temperature sensor for my turbo (obviously not applicable to yours)
After doing so, I bled the cooling system and filled as needed.


Now I can do all the aforementioned activities without the coolant ever reaching the upper white tick (right below the red) on the dash gauge. In fact, the needle sits in the middle of that tick and the one below it once the car is warmed up no matter what driving conditions I get into. Try replacing sensors or at least cleaning off the crap between the connectors and the sensors.

I should also mention that prior to changing the sensors, I fiddled with all the other usual stuff with little to no effect on the temperature:
flushed radiator
replaced thermofan switch
replaced fan relay
tightened up any hoses that I thought were leaking
bled system many many times

[swimmingly]

And here they are...



One more. Just for fun...

[SolReaver]

Polished aluminum parts, Niiice. I concurr, Clean the contacts and the grounds. You could test the temp sensors, but at 120k replacement is not a bad idea if you have issues.

[BerkeleyChemist]

Wow, I always wanted to join this forum. This is unbelievable how many people responded to my dilemma. The switch was replaced recently. The relay on the other hand on this car was not. I bought a brand new one, but insisted I could still use the original. The dual post relay only had one post making contact. So I took it apart and bent the other terminal so it made contact again. I am willing to bet it is making weak contact, thus limiting current or not making contact at all at times. I am still updating rubber hoses, plastic tank, cap, thermo, fluid, of which I was using 50/50. The water was garden hose quality and I really didnt think of using WFI (water for injection) low conductivity water from the biotech lab, but may next time I flush. I could formulate a mix that has good heat trasfer. The airflow is probably to blame. I still havent checked to see if I have a Do-Do bird stuck up there in the shroud. I visited a dealer today and realized all porsches sold today are watercooled. All I know is the cooling system and the timing belt require the most attention on these models. Thanks for all the responses.

[BerkeleyChemist]

Oh yeah, Patricia Dunn wasn't the previous owner, but she did go to UC Berkeley, which is by the way where that car is danging off the Grizzyly Peak at "the wall"

[BerkeleyChemist]

ok, ok, I managed to check out this car and figure out its problem, well sort of. Both fans are not working. Coolant level is ok. I changed relay and still no fans. I bypassed fan switch which is only 6 month old, still no fans. I test both fans via direct current from battery. Looking at car from front, Left fan works, Right, no way. Right fan...when you spin it by hand feels like a cement mixer. This fan has two grounds and maybe associated with AC control from my schematics. So my gameplan will be replace both fans since they are 25years old and vibrate somewhat. Kinda expensive fix. Well 1000 bucks for all the hoses, clamps, exp tank with cap, thermal controls (ie t stat and fan switch), relays and 2 fans is still cheaper than shaving a warped head. Guess I will have fun this winter season....

[BerkeleyChemist]

...furthermore, I thought it was the ac relay, but that wouldnt expalin the burnt fan, or if the intense load blew that relay as well. I should replace that relay as well. I hate how they made this cooling system coupled with the AC. Its too coplex and hs too many failure points. Total loss of coolinng should be a no-no in designing a car. I almost feel like hard wiring in my own sytem I can turn on when it gets hot. After all this I need a fan blowing on my head but will settle for P Hilton.

[Razorback1980]

If you are going to wish, surely you can pick better than P Hilton! There is one other part to the system. There are some resistors to give you two speeds. You may want to check those as well.

I agree, cooling failures should not ever happen. If there is a failure, there should at least be warning lights to say the fans are not running. I think Techno Duck put some warning lights on his and I plan to do the same along with an override switch.

[BerkeleyChemist]

Are resistors in fans themselves? Or is the resistor under the dash. I have seen two such "resistors." One on a late model 924 forum, which would make sense for these are the original 3 blade old school fans from 83, and it had a picture under the dash. The Atlanta part site has them on the back of the fanblade in a diagram. Are there two sets, one under dash and one on each fan? I wish I could get part numbers. Most sites dont really list them. Looks like another stop to the dealer

[Razorback1980]

Read this post...

cooling fan not run

As pointed out in the post, they are probably located on the firewall under the black plastic piece on the right side of the car next to the cabin fan. Read the diagnostic procedure Techno gave you and you should find the problem in a very short amount of time.

[BerkeleyChemist]

ok, I got newer fans that both work. But before I installed them I thought one on the old fans worked, but was wrong. When I tried to hook the ac fan up to the main fan wiring, I found it put a very heavy load on the system. I was testing it when I found out it was nearly seized putting a heavy load on the AC circuit and cooling fan circuit. I was testing with the car hot and the A/C on. Before I remember testing the circuit with a multimeter and found 5 ohms. I haven't tested the resistor or located it yet but think that link helped. I was afraid the heavy load damaged the A/C compressor and or other components such as the climate switch or low pressure switch. The newer 3 blade fans I bought for $74 are in. The drivers side fan seems to spin half speed with the A/C only, the other is off. I jumper the temp switch from the radiator and both spin fast. No fuses seem to have blown. The relays seem ok. I will check the resistor after installing a switch to ensure half speed cooling. There is so much leakage about the passenger side of the radiator near the bottom where the lower hose connects. I hope the radiator isn't shot. The hose is from 1982. I get a drip from the water pump block off and large hose. This is turning into a wild project. The temp sensor is only 6months old and the radiator is about 10 years. Judging from the scale like build up on the side and those plugs that look like stalagmites...just change out everything, so easy a caveman can do it I suppose. I think my mothers calling, I'll put her on speaker.

[BerkeleyChemist]

Another strange side note. This car, 1983 last 4 numbers of the vin are about 4000, so is called for wacked expensive 3 baldes fans that are the same size as other 3 or 6 blade motors. The weird part is that the A/C relay is only 4 Pin single throw, not the 6 pin you always see for about 44bucks. If you look closely at the panel, there are only 4 little copper tabs in the plastic housing. The original realy was still in there.

1 more thing, when I was paranoid I blew the compressor solinoid, I found it to be about 3.3 ohms. I recall it wasn't coming on and I guess the reason is the temp sensor wasn't feeling the 40 degree weather. After I huffed and puffed, it came on only briefly a few times. I put a few drops of PB oil on the clutch and it stopped the squeaking noises. Someone out there is gonna tell me thats not good, well, duh, oil on a friction devices doesn't make sense. Since its such a light oil that evaporates quickly, prevents seizing, smells like tangy vomit, and comes from my hometown, well you get the drift. It also works well for high rotating speed air tools. Just try not to get it on the belt. I felt a difference driving, like maybe some drag was lifted from the main, or maybe it was just time to loosen up my buttons baby.