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jeepv8 12-27-2012 03:42 PM

coolant loss
Hi fellow jeepers, i have a question i replaced my radiator recently and hoses radiator cap and found while at idle at operating temp is pressurizes and starts to leak from the radiator cap any ideas guys ? cheers pete:slapfight:

Frango100 12-27-2012 04:00 PM

Re: coolant loss
Did you check the radiator cap sealing surface on the radiator neck? When there is no damage (scratches, nicks, dents etc) to the sealing surface, then probably the radiator cap is bad.
Also did you check that the cap is completely screwed on? And are you sure it comes from the cap itself. I had it once myself, and at that time the liquid came out of the overflow hose, which had a very small crack at the end.

jeepv8 12-27-2012 07:16 PM

Re: coolant loss
Cheers Frank, its all around the neck radiator is very old and ordered cap through morris 4x4, will check it again, while i have you their, when at idle i have noticed the at idle the revs are starting to fluxuate up and down like from 800 rpm to 1000 rpm and on cold start up it goes straight to 1600 rmp for a second or two then drops humps a bit and then deciced to settle ? any ideas you can throw my way to check, Regards peter.

Frango100 12-27-2012 07:40 PM

Re: coolant loss
Hi Peter. This most of the time has to do with a TPS sensor which is starting to fail. Any rough shifting as well?
Could also be a dirty IAC (Idle Air Control) stepper motor/air passage on the throttle body. Since this last one doesnīt cost anything but some time, its maybe the better one to start with. Remove the IAC stepper motor (one connector and 2 Torqx srews, (number 25 i believe) and you have the stepper motor in your hands. Be carefull to not rotate the plunjer when cleaning, or you will end up buying a new IAC stepper motor. You probably will see a lot of black dirt on the plunjer, but also inside the throttle body air passage. Clean it all well, probably the best is to remove the complete throttle body to give it a good cleanup. If this didnīt help, you will (and this is most probably the case) need a new TPS. best is to buy OEM TPS sensor, since aftermarket can be crap and give more problems then solutions.
By the way, didnīt you mention in the first post that you just replaced the radiator?
In attached thread you will see some pictures on IAC cleaning: Lopey idle on an 02' Overland / 4.7HO

jeepv8 12-28-2012 07:28 PM

Re: coolant loss
Hi Frank , sorry i didnt explain that to well, i changed the radiator about 15,000ks ago but not the cap so i replaced the cap about a 1,000ks later,after checking what you said it was a dodgy radiator cap so thats all fixed. I have been trying to buy jeep parts here in South Australia but the dealer here is brutally expensive, for instance a track bar replacement here is around $500 aus dollars and no kits avaliable so i sourced one through Kevs offroad. i plan on pulling that IAC sensor today and see how i go and the link you sent i copyed off so i dont bugger it up.I let you know how i go, thanks again Frank the info is great and helpful, regards peter.

Frango100 12-29-2012 02:22 AM

Re: coolant loss
Same thing overhere, dealer prices are just insane. I normally buy my things at (mostly non OEM) or (for OEM parts)
Justforjeeps is a vendor overhere and gives discount, check out their thread.

jeepv8 12-31-2012 09:11 PM

Re: coolant loss
Thanks again Frank i will have a look at both links you sent, have a good new years, regards peter

stashgto 12-31-2012 10:11 PM

Re: coolant loss
Don't forget that radiator caps come in different values make sure the new one is tha same as original. Sometimes I use my pressure tester on the radiator, and let it run to see how much pressure it's building up. If it gets high I'll do a test to see if it's a possible head, or gasket problem.

jeepv8 01-04-2013 06:34 PM

Re: coolant loss
cheers stashgto, i have checked with a tester and found no probs there ended up being a dodgy cap, regards peter

stashgto 01-04-2013 07:20 PM

Re: coolant loss
That's great news Peter, take care Stan

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