engine overheating

[jcdr621]

coolant pushing out overflow, temp goes hot in 4 minutes, compression cyl.2-185psi cyl.4 135psi - cyl. 6,1,3,5 - 200psi
took off intake manifold and front ports for coolant are clogged
I am at an inpass if I should look into cylinder heads with this compression
not blowing any white smoke
oil is not milky
125000 miles

already changed radiator, thermostat, water-pump

[pierrot]

A belated welcome to SaturnFans, jcdr621!
How about providing some basic information on this vehicle. Year? Engine size? Maintenance history?
It is possible to have a defective newly replaced thermostat along with the clogged intake manifold cooling system ports. You may need to test for exhaust gases in the cooling system. Here's a sample of a tool designed for this diagnosis - http://www.blocktester.com/

With one cylinder having significantly lower compression than the others, it might be best to seek out a professional opinion on this matter. In the end, you may have no other choice than to remove the cylinder head and have it tested. Nevertheless, this is conjecture on my behalf. I cannot know with certainty. You may also try looking into online forums - if they exist - for the other GM "cousin" models to the Relay: Chevy Uplander, Buick Terraza, and Pontiac Montana.

[jcdr621]

thank you pierrot

2005 Relay front wheel drive 3.5L
tune up done 30000 miles ago
oil change done every 6000 miles mobile 1 syn.

I pulled off the intake manifold and found the front ports clogged -- I am going to try to clean out the intake manifold and heater core

[hendryjullius]

good day

[hendryjullius]

Here mentioned about engine overheating. We all are using various mechanical devices but ignorant about how it works and what all are its internal features. But going through this site we online computer repair get an idea about the devices and its working.

[Packard]

check the oil for milky fluid.

Do radiator cap pressure test with this device . also with below tool .
Do coolant pressure test. Maintain 15psi of pressure while looking for leaks . . Leaks will cause overheating. Most parts stores allow u to rent them.


I dont know vehicle history . A stuck closed thermostat can cause this behavior too.A thermostat needs to open at a certain temp allow the engine to heat up to temp to get into closed loop state.

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[Packard]

How often are you having to refill the radiator? Do you have white smoke?
White smoke if u see this check the oil on the dipstick for milky oil. If so possible blown head gasket.