deliriousga

The A/C didn't work when I bought the shark last October and it turned out the sender wire to the compressor was unplugged. I plugged it in and it's been working fine.

Yesterday we got to 86 degrees and on the way home in heavy traffic with the A/C on the overheating warning light came on. I turned the A/C off and the light went off immediately and the engine cooled down to about 3/4 of the way through the "safe zone" on the guage. I checked things when I got home. Both fans were running, but the coolant was down about 1/2 gallon (I forgot to re-fill it after checking the TB tension recently). I added water and thought that would take care of it.

Today we got to 90 degrees and traffic stopped on the way home. The guage started climbing again so just before it hit the top line where the warning light comes on I turned off the A/C and the temp dropped some again.

Both times after I turned off the A/C and we started moving again the guage went back down to between 1/2 and 2/3 of the way through the "safe zone". Even when traffic stopped again the temp didn't shoot up with the A/C turned off.

One thing I've done recently is install a bra I got for the b-day. It has netting across the intake slots in the bumper, but I don't think that would cause a big problem with lack of air.

Any ideas about where I should start?

Randy V

Putting a bra on a 928 is like putting a moustache on the Mona Lisa - IMHO.

You say when you turn on the AC button the auxilliary fan comes on every time?

Red UFO

My 83 does the samething. Its an airflow problem. On the freeway it will stay down but in stop and go traffic it heats up. I know the fan clutch is good, no belly pan. But I don't think its fixible either. Some sharks are hotter and nobody seems to know why.

But then again when its 90 or more out, its very hard to keep it cool.

SharkSkin

I had the same problem with my 78. it turned out that only the top 8" or so of tubes in the radiator were flowing. Mark @ Devek helped me diagnose it with an IR thermometer(on my list of tools to get, thx for the reminder). I could see that the bottom of the rad was cold, while the top was hot. A Devek radiator and an upgraded cooling fan did the trick. Now I can idle as long as I want on a 100° day, and the needle stays in the middle. More details on my site.

deliriousga

Sorry Randy, but my front bumper is not in great shape paint wise. Rather than pay a lot to have just the bumper re-painted I asked for a bra to put on it for a couple of years. Then the whole car will need a re-paint and I'll have whole car done in a different color.

It seems that the auxilliary fan comes on every time the compressor starts. It does when it's parked anyway.

Fogey1

My '83 got to just above halfway in August Texas Stop&Go. Than which there is little worse. There's something else going on. I second the recommendation for the non-contact IR thermometer.

Have you tested your coolant cap? Made sure the system is purged of air? IMO, they don't "all do that." Good luck.

MikeN

You simply have something wrong in the cooling system......I can drive my GT with it being 100 degrees outside, stop and go traffic, A/C on full blast, and it won't even get near overheating.

Time to......

Inspect all hoses, inspect for any leaks, replace cap, replace thermostat and seal behind it, and as others have suggested, diag the radiator. Make sure both fans are running at full blast when the car is hot and the A/C is on. It never hurts to also take the radiator out and clean all the gunk out of all the exterior cooling fins.....and do the same for the condenser in front of it. You will be amazed at the amount of junk that will come out.

It's not unsolvable, just something that needs to be chased down.

deliriousga

I'll start chasing. I've already replaced the hoses, thermostat/seal and changed out the coolant when I did the TB/WP job. I'll clean everything out and order one of those tools to check the radiator temps up and down and see if I can find it.

Thanks guys!

WallyP

John - Guess what I did yesterday! BTDT

First thing to do:

Open the hood. Crank the engine. Turn the A/C on. Look closely at both cooling fans, and feel the airflow coming off the fans (Keep your fingers clear!!!).

You probably have an airflow problem, and the fans and their control system are the most likely cause.

Remember that there is a separate fuse for each fan.

kshipp

It's ironic that I read this thread today. I took my car out this past weekend and noticed it seemed to be running hotter than usual. I was cruising down the interstate @70mph, with the A/C on and the fan setting on "2". The outside temp was near 90 with humidity around 65%. After about 45 minutes, the temp. guage was on top of the last white mark ( I don't recall the actual temperature ranges).
I'll have to consider some of these tips.....that seems to hot for just 90 degrees w/the A/C on.

Daniel Dudley

Not likely that you have a fan running backwards but it does happen.