5 yrs ago my vans temp gauge rapidly started to shoot up into the danger zone. It was a very hot day and I was pulling a steep hill at the time with the ac on. I quickly shut off the AC and switched to full heater and fan. All is fine the rest of the year until the summer time. It will happen suddenly and the car has to have the AC on to get this to happen. Is this blown head gaskets? For 5 years no problems with the car and overheating. Like I mentioned, it shoots up fast too! Hard to induce, very hot days with the AC on and under a load like a steep hill.
Thank you for having this website availible, if you are able to help me, I will help you in kind.
It could be low coolant, bad thermostat or a clogged radiator.
April, 28, 2012 AT 3:24 AM
Part of my message was not posted. First time for me to use this site. When this first happened 5 yrs ago I have replaced the radiator, cap, thermostat, flushed system and tried block check. This happens only one month out of the year at it's hottest. The car has to be climbing a hill with the AC on and the weather needs to be over 90 degrees F. It's difficult to replicate the problem and when it happens the temp. Guage "shoots" up. I quickly turn off the AC and run the heater to bring the temp. Back down. I have used the car on almost a daily basis for 5 yrs with no problems. Run the AC too, just not on the hottest days. Never seen anything like it. I have heard bubbling from the overflow tank from time to time. We live up on a 3 or 4 mile hill. I add coolant on a regular basis. Maybe a pint per month at worst but, still adding.
My best guess is I have a small crack in one of the heads that only opens up under extream conditions.
Would rather diagnoise the problem before tearing the engine down. When I used the block test I could not replecate the conditions to the point where it would climb the gauge. The only other way I could get it to heat up was to run it very hard and it seemed a bit on the extream or excessive side. I would think over time if it was head gaskets it would degrade to a more observable condition. That's why I think it is a cyl. Head crack.
The rear bank does not look like the friendliest place on earth to be spinning wrenches, more like busting knuckles.
April, 28, 2012 AT 12:42 PM
Before jumping to conclusions, have a pressure test done that is a leak down test. I would go there first before assuming the worst.