Mechanics

OVERHEATING PROBLEM

2001 Chrysler PT Cruiser • 4 cylinder 2WD Manual • 129,000 miles

Ok here goes. Car overheating problem. Owned car for two years, my buddy owned it for 4 years before that. No issues, but neither changed radiator fluid. So went ahead, did flush, replaced thermostat. Still overheating. Watched during flush/fill for engine to heat up and watched water flowing correctly in radiator. Car runs fine for first 8 to 10 minutes, with water temp in mid-range as always. Then it takes off and overheats. Only way to stop car from boiling over is to turn on heater to full blast. Air is super, super hot. Funny thing is, after it heats up, if I return car to slower speeds (under 50) with heater on, car does not over heat.

So question is, does this still suggest bad or poorly working water pump? Is it possible for this to be a pin-hole leak in head gasket? Crack in block? Fluid is still green and no apparent oil in fluid, no water in oil as that was recently changed as well. This one is really baffling me! HELP?
Avatar
Crash
July 7, 2011.



When the car is running hotter then normal is the radiator cooling fan on?Did it overheat before you replaced the coolant?Do you have a temp gun and multi-meter? First, I would have a leak down test done by a shop to verify head gasket condition. Then I would check the radiator for flow. You can do a temp check from one side to the other. The last part would be checking the water pump. Have not seen many impeller issues with these.

First, the pressure tester I am referring to is a special on that goes in where the spark plugs are that measures the amount of pressure loss over a period of time.
You need a temp gun that will tell the temp of the radiator. This is done externally.
The tools are available for this at a parts store but it is cheaper to spend 34.99 to have a shop check it. The tools will run you 150-200 bucks.

Saturntech9
Jul 7, 2011.
Great questions. Prior to the fluid change, the fan would run. To be honest, not sure now post fluid change. Easy to find out. It does not take much to get the engine running hot. Let me go and find out. Yes on multimeters (I have several) but No on temp gun. Locally AutoZone has them for under $30 (checking harbor frieght now)

Tiny
Crash
Jul 7, 2011.
Lets start with if the fan comes on and also get a temp gun so we can see how hot it gets and what temp the fan is coming on.

Saturntech9
Jul 7, 2011.
Also you never answered if the engine overheated before the fluid change?

Saturntech9
Jul 7, 2011.
Ok good news and bad news. First, good news is fan is coming on properly at mid-range temp. Bad news, car is still overheating.

Yes car did overheat previously. That's what prompted the fluid change. On out of state trip for funeral from Baltimore, MD to Akron, OH, all was well until 3/4's the way on return trip. Car overheated. It was very hot day, so pulled over, ate at a restaurant to let engine cool down, went rest of trip (100 miles) using heater to keep engine cool. It worked. That's what prompted fluid change. Fluid looked dark brown and nasty. So changed fluid with flush and replaced thermostat.

So not that fan is working, headed to Harbor Freight for leak down tool and hopefully infrared temp gun.

Tiny
Crash
Jul 7, 2011.
Dont worry about the leak down tool that is used to find a loss of compression in the engine mostly. You can rent a chemical tester from auto zone for free all you have to do is buy the fluid for it for about 8 dollars that will tell you if you have a blown head gasket. Which doesnt sound like you do I think the fan isnt coming on at the correct temp or lack of correct flow or there is sand debris blocking air thru your radiator.

Saturntech9
Jul 7, 2011.
Ok, do you have a part number or name for this chemical tester? Can not find anything like this on autozone website search.

Any suggestions for clearning or cleaning the radiator? While I am suspect that this is the issue due to the sudden onset of this condition after a long trip.

Tiny
Crash
Jul 8, 2011.
http://www.autozone.com/autozone/accessories/Tools-Garage-and-Equipment/Block-Tester/_/N-25dh
Do you have a air compressor ?If so get a blow nozzle like one of those plastic blow nozzles with the metal tips and blow the fins of the radiator and a/c condensor out.Use your temp gun to see what temp the fan comes on at.Measure the temp right where the upper hose goes onto the engine.

Saturntech9
Jul 8, 2011.
Just got home. Block tester from AutoZone immediately indicated yellow. Ran it 4 times. Air was so hot going in there it warped the plastic chamber : (

Tiny
Crash
Jul 8, 2011.
Question: Will a "block sealer" additive to the radiator fluid help? Does it really work? Is there one brand better than another?

Tiny
Crash
Jul 8, 2011.
Page 1 of 3