Author Topic: How hot is too hot? (Read 4120 times)

sumyungguy · « **on:** March 11, 2007, 04:43:09 PM »

Well I discoverd my auxiliary fan isn't working the hard way.

A few days ago I left the car idling while I was taking some pictures and noticed I was leaking coolant.. I run over to the car and turn it off, the gauge was nearly to the 3/4 mark. I popped the hood and traced where the leak was coming from, right by the radiator cap. I was only 2 miles from home so I let the car cool down a bit and drove home, on the way home the temp was fine and wasn't going past 1/2. Get home and let it sit to cool down enough to open the cap, while sitting not a drop leaked out. I open the the cap and see theres a little hole at the top of the chamber that looked to be a overflow hole maybe? The car had been a little over filled on coolant when I got it and I thought it was maybe just getting rid of the excess water. My buddy has a e30 325 and he said his car did the same thing and it didn't happen again, so I continued to drive it with no problems. But his cars cooling system is different cause it has an external reservoir.

Yesterday I was on the freeway and ran into some traffic at the tolls, sitting still idling the temp starts going up. I drove down the shoulder not wanting to end up with a dead car in traffic and as I was going down the shoulder (5mph) the temp went right back down. I managed to get back into the traffic right at the toll and continued with no temp problems.

Last night I let the car sit and idle under close watch, sure enough the auxiliary fan never kicked on and the car started to get warm, shut it off and now I'm gonna dig into the fan.

I was told when I had my e36 325 that if it goes above 1/2 that the motor probably blew the head gasket or overheated cause the gauge is pretty dumb and only goes up when its too late. Is this the same case on our motor's? The oil cap and spark plugs show no sign of water, and the car still runs fine. Anyone else run into this issue? And what is too hot for our motors?

RED IS 91 · « **Reply #1 on:** March 11, 2007, 06:34:26 PM »

Turn on your ac with the motor running and see if the fan starts.
If it starts then it may be your thermo switch
There is a test in the bentley manual for the thermo switch

sumyungguy · « **Reply #2 on:** March 11, 2007, 06:57:52 PM »

just checked it.. it does come on when the ac is on.. but shouldn't it also come on when the temp reaches a certain point to act as a helper fan? My buddies e30 325 does, but for all I know the previous owner could have installed a temperature activated switch. I know its totally different but my integra's auxiliary fan would turn on when the car would reach a certain temp..

sumyungguy · « **Reply #3 on:** March 11, 2007, 09:21:55 PM »

Update: The fan is supposed to come on during a/c operation and when the engine reaches a certian temperature in 2 stages (194*F low speed and 210*F high speed). The fan turns on when the a/c is on no matter what the temp is. There are also two relays for the fan, low and high I'm assuming.

So that means: A. The sensor's not reading the temp. or B: The relay's are bum. What do you guys think?

EDIT: I may just wire the fan to turn on with ignition, Ive done this to most of my cars.

ecpreston · « **Reply #4 on:** March 12, 2007, 07:53:18 PM »

FWIW, 3/4 is nothing on an e30. Our gauges aren't super buffered like E36 (I dumped all the coolant out of my E36 before my gauge ever budged). I think that switch that kicks on the fan on high at 210 is somewhere above 3/4. You didn't do any harm. If your fan is still working when the AC comes on, I wouldn't even bother fixing it. Just turn on the AC if it's sitting!

sumyungguy · « **Reply #5 on:** March 12, 2007, 08:15:03 PM »

Sweet thanks..

I ended up tracing it to the fan switch, I just wired it to run on low all the time and Im going to put in a switch for the high if needed. The fan switch is very simple, it's a open/close loop ground switch, so just connect position 1 into 2 for low and 1 into 3 for high. No + to deal with and your still using the stock relay's and fuses.

ecpreston · « **Reply #6 on:** March 12, 2007, 08:48:24 PM »

You won't need high unless you're in the desert and your mech fan is broken or something. You should be good to go

sumyungguy · « **Reply #7 on:** March 12, 2007, 09:09:38 PM »

Quote from: ecpreston;21129

You won't need high unless you're in the desert and your mech fan is broken or something. You should be good to go

Yeah I know, thats why I figured Id put a switch inside (probly in the glove). It gets in the 100's out here and I don't want to get caught in traffic (which is pretty often) and have to pull over and hook up the high.

Moma says better safe than sorry.. :p

Crunk3 · « **Reply #8 on:** March 12, 2007, 11:01:50 PM »

My Temp gauge just barely gets past the 1/4 mark, is that bad?

sumyungguy · « **Reply #9 on:** March 13, 2007, 01:43:02 AM »

broken thermostat.. at least its broken open..

If its bad that depends on what kind of driving you do and if want to use your heater effectively (It probably doesn't work that great now?)..

Alpine003 · « **Reply #10 on:** March 13, 2007, 07:58:19 AM »

Quote from: sumyungguy;21125

Sweet thanks..

I just wired it to run on low all the time and Im going to put in a switch for the high if needed.

I would just replace the fan switch as you'll be reducing the longevity of your fan if it's constantly on. It might break when you most need it. Just a thought...

sumyungguy · « **Reply #11 on:** March 13, 2007, 10:53:05 AM »

The fan being on low all the time isn't going to hurt it. Ive done this to most of my cars cause sitting in traffic is a daily chore, where Im at in CA it hits 100* in the summer.

kowalski · « **Reply #12 on:** March 13, 2007, 01:59:16 PM »

what if it doesn't go past half, new tstat new rad, and the heat is damn hot.