random overheating

slammervan73 · Posted: Mon Jul 20, 2009 7:26 pm Post subject: random overheating

hi i have a ej22 in my bay.

Fitted with two 205gti rads under the floor pan with a scoop underneath its all linked with silicon hoses and i use a rover 400 header tank.

i use the van everyday and i drive 30 miles to work each day and its normal running temp is 88-90 degrees.

I drove the van up to bug jam and raced it saturday and it was fine, but randomly on the way to work today and its happened a couple of weeks ago the temp got up to 120 degrees and blew all the water out the top of the cap, i pulled over let the van cool down and re filled it taking the top hose off to try and ensure any major air locks came out and refitted it and went on my way and it was fine. Gave it some sh*t on the way home from work and no problems.

Any ideas??? its rather enoying because i cant work out the problem, its a pressure build up of some sort but i cant work out how? its fine then will randomly happen out of know where.

Header tank not high enough?

cheers guys
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2.2 legacy powered bay

easy-does-it · Posted: Mon Jul 20, 2009 7:38 pm Post subject:

Did you use a new cap on the header tank?....

Only my nan's metro used to do the same thing and after a lot of time and grief it ended up being the cap..apparently it happens a lot on rovers
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'76 bay going superfly TDI

slammervan73 · Posted: Mon Jul 20, 2009 7:42 pm Post subject:

yeah after it happened the first time i replaced the cap, its really odd im thinking of looking into turbo engine's but cant risk it until i sort the problem out.

thanks for the suggestion though.
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2.2 legacy powered bay

Bigbadbugga · Posted: Mon Jul 20, 2009 7:42 pm Post subject:

sounds like the head gasket might be going, its common for the exhaust to leak into the cooling system and pressurise it, emptying the water out.

get it checked out, there is a kit you can buy that tests for exhaust gas in the coolant, it has a green liquid that turns a different colour when exhaust is present.

frost automotive sell it, or some engine specialists can test for a small charge.
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Located near Liverpool.

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Bigbadbugga · Posted: Mon Jul 20, 2009 7:47 pm Post subject:

here's the stuff

http://www.frost.co.uk/item_Detail.asp?productID=8682&frostProductName=Block%20Tester&catID=&frostCat=&frostSubCat=&subCatID=
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Located near Liverpool.

Building a full custom 1972 Beetle with an EJ25 (n/a sohc),Porsche 944 IRS conversion and Rjes bellhousing.

slammervan73 · Posted: Mon Jul 20, 2009 7:49 pm Post subject:

ok that sounds like its worth testing, i think my mates got one of those kits.

cheers
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2.2 legacy powered bay

ElusiveStranger · Posted: Mon Jul 20, 2009 11:26 pm Post subject:

My money's on a vapor lock in the return from your rads.
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richbaker78 · Teacher of Padawans Joined: 31 Jan 2006 Posts: 1298

ive had the very similar scenario happen on my dads car. I immediatly expected airlocking due to head gasket as suggested above.....however it was too randomly occuring and in the end it turned out to be a faulty thermostat. An easy thing to check and fix.

slammervan73 · Posted: Wed Sep 09, 2009 9:56 pm Post subject:

right guys, just to keep u updated. The random heat rise in temp at speed. If a decent speed was being done the temp gauge would rise to 110+ then if it was ignored the temp would incline back to a decent running temp. BUT if it was town driving the temp gauge would keep rising until i pulled over and turned the engine off. It would seem the thermostat was not opening.

So it would suggest air in the system.

First i tried raising my header tank, which didnt work.

Ive now drilled and tapped the inlet pipe into the engine for the water and created a breather returning to the header tank, and it would seem that has curred the problem! RESULT.
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2.2 legacy powered bay

rjes · Posted: Wed Sep 09, 2009 10:03 pm Post subject:

Is your fan(s) not coming on, or is the temp continuing to increase even though the fan has come on?
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slammervan73 · Posted: Thu Sep 10, 2009 6:38 am Post subject:

The fans come on fine, the times that i did stop i put my hand round the pipe coming from the stat and it was still cool.

It was odd thou, it was really intermittent, i could go weeks and nothing would happen then it would do it. It started after i fitted my second rad.
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2.2 legacy powered bay

slammervan73 · Posted: Thu Sep 10, 2009 6:48 am Post subject:

oh yeah and stat is brand new, and a genuine subaru one. i thought that was my problem originally.
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2.2 legacy powered bay