John Galt

Updates:
1. There is no white smoke from the exahust.
2. I've validated that the fans come on at low speed (i guess) at 226F.
3. I've validated that the fans come on when the temp is 185F and the AC is on.
3. I've checked the fan fuses, they are all good. Is there a procedure to check the relays?
4. I've burped the system both at the block and the standard method.

What now?


I have a stock 2002 C5 1SA with manual transmission and about 75k miles on it. I bought the car new and have had very few problems: steering column lock, oil pressure sensor and that is all. Until now.

Problems
1. Starting about one month ago, when I park the car after a drive of 15 minutes or more I get (what I think is) coolant boil over leaking on the ground behind the front passenger wheel.

2. Coolant temp is usually around 200-205, but now is going to 235 when idling in traffic and a bit lower when moving. I realize that 235 is not a critically high temp, but the car has been running under 210 for 10 years and has suddenly spiked up, so something is wrong.

3. I often get little or no heat from the HVAC, but it works normally sometimes. No pattern that I can detect as to when it does and does not work.

All of these problems came on in the same timeframe. The car is otherwise working and running fine; good power, good gas mileage.

Last time I parked, I could hear the hissing from the pressure forcing the coolant out.

Troubleshooting
I've topped off the coolant several times. I’ve noticed that the temperature stays a bit lower when I have it topped off, but it goes up to 235 when it is down a bit. Bad radiator cap? Maybe. But does that explain the heater not working well?

The vent and AC work well. The HVAC fan blower is working and properly responds to speed adjustment settings.

I have not replaced any parts in the last 10,000 miles. I've never replaced the water pump or any of the other cooling system parts.

I did a coolant flush a year ago: dexcool + distilled water 50/50.

I am not hearing any squeaks or strange noises.

There is no debris in the radiator intake area.

I have not checked any fuses or relays.

The radiator cap is on tight

My car is stock, so the air dam and all the other parts are there. This car has not been in any accidents.

I think the leak is only when I’m parked and not running, but I can’t be sure.

There are no really obvious leaks under the hood..except for straight down from the rear of the overflow tank where I can see it is wet on the (sub?) frame (at the bottom of the car, straight down from the left rear of the overflow tank). That leak point matches close to where the water is coming out from the car on the ground.

I've verified that the fans are both spinning and providing suction through the radiator (both fans held a piece of paper on the radiator). Is there a procedure to verify they are spinning at the correct speeds? On my C4, there was a high speed/low speed fan test procedure, is there a similar test for the C5?

I pulled the codes from the DIC. I have not pulled codes in four years, so there were several, but all are historical.

IPC
B0516 - Speedometer circuit malfunction
U1160 - Loss of comm with LDCM

Radio
U1064H - BCM Comm issue
U1096H - IPC Comm issue
U1016H - PCM Comm issue
question: why does the radio need to talk with any of those systems?

A0 LDCM
B2262H - Battery 1 circuit
U1064H - BCM Comm issue

A1 RDCM
B2283H - Battery 1 circuit
U1064H - BCM Comm issue

I replaced the battery a few years ago; I’m guessing that could account for many of these codes.

Any ideas on this problem?

Potential things to try...what do you think?
1. Burp coolant system
2. Fuse/relay check (which fuses and how do you check the relays?)
3. Replace radiator cap. Is there a way to test the radiator cap?
4. Replace t-stat (is this warrented?)
5. Replace overflow tank (is this warrented?)
6. Replace water pump (is this warrented?)
7. Just stop worrying?

Is there a procedure to test the fans are spinning at the right speeds?

Is there a procedure to burp the heads or block?

Is there anything I should do about the DIC codes listed? Should I check if I have a ground issue? Does anyone have a ground check procedure?

Jeff in Den

What condition are the heater hoses in? Could be the source of your leak.

04blackice

Blowing cold air is sign of head gasket going out.possible pin holes..had same prob different car.kept pushing it and finally poured white smoke..red lined temp.had to resurface heads and new gaskets..no more problem

sccs

What do you mean by 'Blowing cold air' ? where from?

John Galt

The hoses look good. The leak would be continuous (when the heater was on) if it was coming from those hoses. The leak seems to only happen when I park and turn off the car.

John Galt

The heater works fine sometimes, usually after the car has run for 20 minutes or so.

JoeyOKC

Start the vehicle and turn on the air conditioning. Get down by the front of the vehicle and feel for air flow and fan operation. If the fans aren't coming on, turn off the ac immediately as the pressure will get very high without airflow across the condenser. If the fans aren't coming on, this is the first step in things to fix.

04blackice

Op said no heat from hvac..that was a sympton for me.car is overheating so u turn on heater and only luke warm air comes out.and i kept pulling over to add water.no help just more white smoke from pipe and still blew warm air.

John Galt

Both fans are running and providing what feels like "good" airflow.

How can I tell if the fans are running at the right speeds?