1995 lexus gs300 overheating assistance please.

[laotionracer101]

By now i'm thinking head gasket or my fan clutch is out. I've done my reading but my problem is some what different from what I have read.
[The Problem] - When I first got the overheating problems the car needed the coolant to be topped off. The problem persists. I have now changed thermostat and radiator cap. The car seems to over heat ONLY while driving, If I was to start the car and let it sit and idle there will not be a problem. Another symptom is that when I remove the radiator cap while the car is cooled and I start it, water blows out. Of course it is air in the system so I let it go on but it doesn't really seem to stop (longest course 30-45min)

 

[laotionracer101]

Still open to any ideas.

 

[BTNH-LC]

First off, if the car is running with the radiator cap off, the water pump can put out enough pressure that it can blow water out. If the car is cooled down, put the radiator cap on and start the car. Grab the upper radiator hose and feel how much pressure there is (careful, it may be hot). If you can squeeze the hose and collapse it while the car is running then more than likely the headgasket is fine. Depending on if you have a manual fan or electric you could have several problems. The manual fan would be the easiest and that would be the fan clutch. If electric, the fan motor may be bad or a blown fuse/relay. Or whatever controls when the fan switches on could be bad, i.e. the ect. As far as the coolant having to be topped off, you've got a leak somewhere. Most common are the water pumps and radiators. Put a clean piece of cardboard underneath it and run it for a while and wherever you get drips you'll get a general idea of where the leak is coming from. Hope this helps. Let me know how it turns out.

 

[laotionracer101]

Well its running without overheating issues right now and i havn't changed a damn thing since the cap and thermostat, but i know it's going to overheat again. Its got both electric and manual fan.

 

[BTNH-LC]

If it's got both then the electric one is easy to check. All you have to do is start the car and turn the ac on. If the electric fan comes on, and it may take a few minutes and only run for a little while before turning back off, then it's working properly. If it never comes on, take the engine speed up to about 2500 rpm while just sitting there and after about a min or two the fan should come on. If it doesn't check the fuses and check to see if the fan has power coming to it. If this all checks out but the fan still won't turn on, you need a new fan motor. As far as the manual fan, with the engine off try turning the fan blades. You should have some resistance though not that much. After that start the car and get a sideways view of the fan to see if it looks wobbly. Then while you're checking the electric fan while revving, if the fan clutch works you should feel it put a load on the motor and the fan rpm should jump higher. Also check for trash that could be blocking air flow in front of the condenser and between the condenser and radiator.

 

[laotionracer101]

Okay.. Now what about the possibility of a blown headgasket/clogged radiator.. This car is giving me headaches.. Its overheating like a mother right now.. I'll try and test the fans to my best ability

 

[BTNH-LC]

Do you have alot of pressure on the radiator hoses while it's running? Any water in the oil or steam coming out of the exhaust when you first start it? If you have any of these then you might have a blown head gasket. Were you low on coolant before you started it? Find any external coolant leaks?

 

[hvyman]

You would only get over heating at stops if the fan clutch was bad.

This is a 2jzge right?

IF you pull over or drop the rpms does it cool back down or do you have to shut it off.

Rent or buy a combustion chamber tester and a compression tester. This will let you kno whats going on.

Any coolant lose? Milky oil? Lose of power? Smoke?

 

[laotionracer101]

It pulls strong, engine feels healthy no smoke, It DOES cool down when i park and idle, I don't think compression test is necessary as I think I have found the problem. I have been refilling it with water, and all of the sudden one day I saw green coolant.. It's most likely clogged, Maybe some sort of a radiator walmart fix. I am going to try flushing it after I get my crx put back together tomorrow.