Cooling System Pressured Only Going up Hill

[kiwi73]

Hi

Have a 1995 RV down here in NZ

Experience pressurisation of the coolant system when I'm towing a load up hill. The water is pushed out of the radiator cap. When I refill the radiator it's fine. It only seems to do this when I'm travelling up a hil with a loadl. Outside of this I never have problems with overheating.

The radiator and cap were replaced 2 years ago. Also the thermostat was also changed.

Investigation on the web offers up the following:
Replace cap - check it's the correct rated cap for engine
Replace thermostat
Pressure testing coolant system check for leaks etc
Pressure test head gasket and intake manifold

Any suggestions/thoughts

Many thanks
Brian

 

[Paul]

Which engine do you have? Maybe worht filling out the intro page.

Rad cap is an easy check. Does outside temp make a difference?
Pressure test of the system also which should eliminate head gasket problems. Most pressure test systems can be connected to the the rad cap also to check when it is blowing off.
Are you running the correct coolant concentrate also?
Was it a Toyota Radiator as a replacement.

There is also a thread running on this by Bat21 with regards a cooling problem that would be worth a read.

 

[Mark Whiteside]

I would check the external rad thins for blockage
and to check if fitted the viscus fan has a good resistance when hot

 

[kiwi73]

Which engine do you have? Maybe worht filling out the intro page.

Rad cap is an easy check. Does outside temp make a difference?
Pressure test of the system also which should eliminate head gasket problems. Most pressure test systems can be connected to the the rad cap also to check when it is blowing off.
Are you running the correct coolant concentrate also?
Was it a Toyota Radiator as a replacement.

There is also a thread running on this by Bat21 with regards a cooling problem that would be worth a read.

Cheers mate

Its a 4.2 litre normally aspirated diesel. Radiator was a Toyota replacement.

Had a cap looks like the rubbers gasket is screwed up and not seated properly. Could have been the cause.

Even though theres no visible signs of head gasket failure still think it's worth a test as you suggested.

Will double check the coolant ratio and check the thread as suggested

Cheers

 

[Bat21]

Brian,

What does your rad header tank look like.... and does it smell in there?

Have a read of this...

I hope it isn't as bad as this...

And I really hope you don't end up doing this....

Let us know

 

[Dave2000]

As menyioned earlier the vicous fan is a regular culprit, can you hear it roaring when clmbing a hill under load, you should be able to with the window open. Many people think that as you are moving the fan is not needed but this is no entirely true.....BTDT.

When I purchased my 80 pretty much ALL the fins were missing leaving just the tubes with the water in, no overheating issue at all before I put in a new rad. MIght be worth checking for rubbish between the A/C condenser and engine rad?

regards

Dave