Help! Over heating

[zeek]

Hello Vette friends, need help. Noticed that my '94 c4 over heats, often after a short drive(4-5 mi). After stopping, I can hear bubbling sounds and see wisps of white smoke under hood. Did the same today. I parked and looked under hood(trying to locate the bubbling sound and locate leak). After opening hood, I saw coolant rolling down hood into head lights area(Passenger side). Couldn't find leak so decided to follow the bubbling/boiling sound and white smoke. I identified the boiling sound and smoke as coming from behind the engine(Most on passenger side). If so,

1). What can it be?
2). Estimated cost to fix.

Thanks in advance for all help given.

 

[DonB]

Hi Zeek. What is your temp gauge reading? Mileage on engine? Are there bubbles coming up in surge tank? Is oil milky or anti-freeze mucky? Sounds a lot like a head gasket/cracked head issue. Aluminum heads on a cast iron block, running at high temps. It's only a matter of time.

This is a very common issue with C4's. I have one and just finished my complete overhaul. NOT to freak you out, but it is a well documented issue.

I'd do a cooling system pressure check and a compression test. but if you have bubbles coming up in the surge tank by the firewall(check it with the cap off at idle on a cold start ONLY!), DO NOT open that HOT!That generally indicates air from the combustion chamber being pumped into the cooling system via a blown head gasket, cracked head, etc.

There are also a lot of heater hoses and connections in the area you mentioned. There is a coolant line that attaches to the intake manifold by the distributor and the corrugated EGR tube(right rear of intake manifold.) CAREFUL the EGR tube is real HOT!

Hope this got you pointed in the right direction. I'd rule out the simple stuff first. like simple leaks first. Pressure check the cooling system. Keep us posted.

 

[Hawk73ku]

Hello Vette friends, need help. Noticed that my '94 c4 over heats, often after a short drive(4-5 mi). After stopping, I can hear bubbling sounds and see wisps of white smoke under hood. Did the same today. I parked and looked under hood(trying to locate the bubbling sound and locate leak). After opening hood, I saw coolant rolling down hood into head lights area(Passenger side). Couldn't find leak so decided to follow the bubbling/boiling sound and white smoke. I identified the boiling sound and smoke as coming from behind the engine(Most on passenger side). If so,

1). What can it be?
2). Estimated cost to fix.

Thanks in advance for all help given.

I would be looking at heater hoses based on your description but my 96 also hast the tank fill reservoir in that area.

In my 96 I have an oil temp and water temp gauge and they should sync up after the engine warms up. My water temp gauge runs off a sensor on the block but another sensor on the water pump feeds the PCM. You can view that temp with scan tool.

Also on my 96 I have a bleed valve on the thermostat that I can bleed air off which helps with pressure.

You should probably do a pressure test and chemical test. Both test devices are available from Autozone loaner tool program.

Hey it's hot this time of year and corvettes are notorious for heating. Mine runs around 230 at idle. Some people turn the AC on to force fans on in stop and go driving.

 

[DonB]

I would be looking at heater hoses based on your description but my 96 also hast the tank fill reservoir in that area.

In my 96 I have an oil temp and water temp gauge and they should sync up after the engine warms up. My water temp gauge runs off a sensor on the block but another sensor on the water pump feeds the PCM. You can view that temp with scan tool.

Also on my 96 I have a bleed valve on the thermostat that I can bleed air off which helps with pressure.

You should probably do a pressure test and chemical test. Both test devices are available from Autozone loaner tool program.

Hey it's hot this time of year and corvettes are notorious for heating. Mine runs around 230 at idle. Some people turn the AC on to force fans on in stop and go driving.

Hawk you said your engine runs at 230*. I installed this kit from Corvette Central #244074. It is an additional low temp fan switch you install in the cooling jacket plug in the left head between plug numbers 1 & 3. You then splice it into the activation leads going to the fan relays. It is awesome! I'd highly recommend it. My engine stays about 180-185 all the time, regardless of ambient temperature. It only costs about $40. You can install it in about half an hour. I'd also put a 160 thermostat in it too.

Regards, Don

 

[Hawk73ku]

Hawk you said your engine runs at 230*. I installed this kit from Corvette Central #244074. It is an additional low temp fan switch you install in the cooling jacket plug in the left head between plug numbers 1 & 3. You then splice it into the activation leads going to the fan relays. It is awesome! I'd highly recommend it. My engine stays about 180-185 all the time, regardless of ambient temperature. It only costs about $40. You can install it in about half an hour. I'd also put a 160 thermostat in it too.

Regards, Don

Good tip! I'll check into it. I recently replaced thermostat and shopped all over town for a 160 and couldn't find one. I would definitely like to have the old gurl running cooler.