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confusing overheat problem

Posted: 13 Dec 2009, 16:20
by quarryman
Now, a few weeks ago I jumped to conclusions about the state of my (sierra) engine. Having replaced the battery, adjusted and cleaned the plugs, and generally just had a good root around the engine bay the van started and seems to run fine.
Took it for a spin - and its cold outside today. After about 10 miles the engine was running very warm, temp gauge for coolant was showing a good 95-100 degrees with a lot of pressure in the system.
Released the valve on the coolant tank after a while and tonnes of steam came pouring out.
Also, I can't get any heat out of the blowers - but I could until I started getting problems.

As for general running, the van seems ok, doesnt want to stall, pulls ok - its just getting very hot somewhere.....

Still - I got my christmas tree in one piece so that's a start - these vans have their uses!

Re: confusing overheat problem

Posted: 13 Dec 2009, 17:36
by Zebedee
Sounds like it could be an airlock in the cooling system.
Had the near exact same problems with my passat a few months back after flushing the system and adding new water/anti freeze. :(

Re: confusing overheat problem

Posted: 13 Dec 2009, 17:45
by Ian Hulley
Is this the Pinto or the DOHC ? I had both (in Sierras) and the Pinto has a high point bleed spigot which has a cap over it (these used to perish and blow coolant everywhere :roll: ) you may need to have the asre-end in the air with that part raised to bleed it properly.

Ian.

Re: confusing overheat problem

Posted: 15 Dec 2009, 09:10
by quarryman
Think you could be on the button there. I overfilled the coolant, then drained through - airlock could be the culprit. I'll try and bleed it at the weekend.

Re: confusing overheat problem

Posted: 15 Dec 2009, 23:04
by Mr Bean
Released the valve on the coolant tank after a while and tonnes of steam came pouring out.
quote]

Exactly right! If it doesn't boil when you remove the cap on a hot engine the chances are you themostat is duff or misssing - i.e not closing. (Just like an astronauts blood would boil if his space suit sprung a leak.) Your cooling system is like a cross between a plumbers store and a pressure cooker. As for the heater not working I agree that you probably have an air lock. The amount of furum space used on heating and bleeding must tell us something about the design of the T25 cooling system... :wink:
Cheers
Wolfie