120 Radiator building pressure and overflowing into reservoir

[Blakey1978 Lurker Find all posts View Profile Close Blakey1978]

Hi guys,
I am new to Prado point and hope you can help me with a problem.
I have a 2004 120 series petrol Auto with 378000klm Been a dream machine.
The radiator reservoir keeps being refilled by the pressure somehow have replaced thermo and radiator cap done pressure test and it only dropped 1-2 psi (apparently not much)
Have also done a compression test on engine Drivers side was 160 - 170 - 175 and passenger side was 190- 190 - 200
The motor is not overheating at all although the top radiator hose feels like it wants to explode and feels boiling.
I am thinking maybe head gasket or cracked head anyone else have any thoughts or suggestions?
Cheers in advance

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Classic sign of a faulty head gasket, any oily residue in the coolant?

[turtlewa Member Find all posts View Profile Close turtlewa]

Cheap option try a bottle of Sure Seal the stuff works well

[Blakey1978 Lurker Find all posts View Profile Close Blakey1978]

Thanks for the feedback couldn't see any oily residue when the guy at natrad did some sort of fume test he said he could smell it but it didn't show on the test.

[Blakey1978 Lurker Find all posts View Profile Close Blakey1978]

I put a bottle of K Seal in it today hoping it would work and it hasn't as yet same issue I am thing head gasket got a Qoute of $550 for a VRS kit $150 for head bolts and $88 for a head shave, think I will bite the bullet and start pulling it apart.

[Whitey Shockie Maker of the Month Award Find all posts View Profile Close Whitey]

Hey Blakey,

It's a head gasket for sure. Unfortunately on early model 1GR-FE motors, the cylinder head gaskets had issues, typically on cylinder number 6.

See here for examples;

http://www.toyota120.com/forum/showthread.php?t=22777

http://www.expeditionportal.com/foru...th-Gen-4Runner

https://www.tacomaworld.com/threads/...ptions.338360/

This thread has a good "how to guide" for tearing down the motor;

http://www.toyota-4runner.org/4th-ge...4-misfire.html

I've just had everything apart on my 1GR-FE to fix a leaking timing cover plate, it's not that much more work to pull the heads, and is definitely a job you can tackle at home!

Here is also a small video where the mechanic has pulled the number 6 spark plug and is blowing air through, which you can see bubbling up through the radiator, exactly the symptoms you have;

https://www.youtube.com/watch?v=LM4Rfq-wvag

Good luck with getting it sorted!

Best

Mark

[Blakey1978 Lurker Find all posts View Profile Close Blakey1978]

Thanks for all the links Mark much appreciated will start to pull it apart next week will let you know how it goes..
Cheers

[Corigator Avid PP Poster! Find all posts View Profile Close Corigator]

I assume you have checked the Radiator cap is sealing properly. Might be worth checking before you go the head gasket solution

[Blakey1978 Lurker Find all posts View Profile Close Blakey1978]

Yeah sure did and I replaced the thermostat also, the temperature gauge decided to spike today so convinced now it's the head gasket ��

[Wtrxprs007 Senior Member Find all posts View Profile Close Wtrxprs007]

I'm not sure if I understand the issue but Isn't the coolant meant to overflow into the reservoir from thermal expansion?

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

The reservoir should stay between the cold "low" and "hot" markings which indicates normal operation. If you over fill then you would expect some to be expelled. But, if it's moving further than those two marks, usually with air expulsion, then you have a problem. Just replaced the cap on my son's XR8 ute. There was a slight leak of coolant near the top manifold. This was cured by replacing the cap.

[Wtrxprs007 Senior Member Find all posts View Profile Close Wtrxprs007]

Yep. All normal if it stays between the lines but not normal if it goes over too much and you see some come out or if it goes under which means there's a leak