boiltheocean

Coolant Circulation Issue?

19 posts in this topic

Hi guys,

 

Had a bit of a scare on the way back home from the Nurburgring today when at the tunnel my water temp started rising fast. The non-pressurised coolant filler was quite a bit higher than I left it which I found odd. Being desperate my mate unscrewed the cap above the turbo and tipped some water in there. That seemed to work as when I dropped him off in Milton Keynes after a steady 70mph run back from Folkestone the temperature was completely normal. I've driven on back up to the Midlands and as I was reaching the slower roads back to home the temperature started rising again. I let the car cool down and the filler tank is now even higher than before (looks like it's actually blown some fluid out the top...) and the tank by the turbo which was brimmed is now empty, even when I squeeze the pipes.

 

To me it seems all the coolant is going one way and not coming back while it's running. I don't know if we've made it worse by removing the pressurised cap? Any ideas what the problem could be or what I can do to fix it?

 

This is just added insult to an already bad weekend. I was out there photographing the 24h race and both cameras I had died in the massive hail storm that hit the track, so I only got to shoot the first 50mins of the race.

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It sounds like your head gasket has gone!

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That's what I'm worried about. I can't see any oil in the coolant tank and I'll talk to my local dealer tomorrow but I really, really hope it's not the head gasket. I've already lost a few grands worth of cameras this weekend.

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The 2.5 is renowned for blowing its headgasket, plenty of threads on here about it, hope you get some good news though.

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if it's gone the same way as most of ours have gone you won't see any of the usual warning signs

 

As above look up some of the threads on here about it. Mine went a few years back but was so subtle there was actually a bit of argument about whether it had actually failed or not. In the end my local specialist gave me a set of procedures to try and that eventually caught it. I was pressurising the coolant tank on boost because the head bolts were stretching.

 

As a quick bit of advice take it for a short sharp blast (flat out in 4th will give close to maximum boost) and then immediately check the tank at the front. If you see any bubbles then your HG is doomed

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When my HG went, same symptoms as you by the way.... whilst I made my mind up on what to do & who i'd trust to do my re-build!

I continued to use my RB for a few months, OFF BOOST, just making sure the header tank was topped up with coolant & it drove fine. Any small amount off boost would cause the coolant temp to rise though!!!!

 

But on top of my HG shi77ing itself, once stripped I had piston ringland failure too.

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Ross nailed it with that test. Exact symptoms replicated. Fortunately I've got Chevron Motorsport not too far away so it's going to see them very soon. No doubt they'll confirm HG failure and I'll figure out where to go from there.

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the Subaru engine is not like a traditional inline engine as the cylinders are simply surrounded by water and dont x-contaminate across into the oil ways

 

as above the lift the heads on boost most commonly, pressurising the coolant system and blowing water into/out of the overflow bottle.........

 

main reason we do CDB conversions https://www.facebook.com/ASPerformanceUK/photos/?tab=album&album_id=940150562663346

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Ross nailed it with that test. Exact symptoms replicated. Fortunately I've got Chevron Motorsport not too far away so it's going to see them very soon. No doubt they'll confirm HG failure and I'll figure out where to go from there.

 

Have you been & seen Simon at Chevron yet?

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Yeah, took it in a few weeks back and they confirmed HGF, now just waiting to have work done as they're super busy at the moment.

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Yeah, took it in a few weeks back and they confirmed HGF, now just waiting to have work done as they're super busy at the moment.

 

What spec you going for?

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I'm not sure about that yet. The HGF was diagnosed from taking it for a run out and as far as I'm aware it's not been taken apart yet so we don't know the full extent of what needs doing.

 

I'm also not entirely sure what I should be having done. I'm trying to read up on a few previous build threads to get an idea before Chevron get back in touch with me but I'll probably be following a lot of guidance from Simon. I'm not looking for any power gains as being young makes it hard enough to insure one of these things so I'll probably just look at replacing the known weak links in the engine.

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that's what I said when I started... and I'm sure you're read how that turned out :blum:

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Collected the RB today after having all the work done at Chevron. I've got a few miles to run in before I can give it the beans but it feels absolutely fantastic, pulls like a freight train.

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what spec did you end up with in the end then?

 

How many arms and legs did it grow? :blum:

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Had the block and heads completely overhauled. Uprated studs, pistons, head gasket and full set of new seals. New Main and Big End ACL bearings, cam belt kit and Exedy Pink Box clutch.

 

The turbo was found to have a small crack in the usual place so that needs sorting at some point but it's not a huge concern at the moment. Simon says it's good for low 400's in terms of HP but obviously limited at the moment by the stock turbo. Like I've always said though I'm not looking for any more power, just having it back running without it overheating is great.

 

I should start a proper thread for all the work I do on this car as I've got a few plans to make the interior a slightly nicer place to be when the funds allow.

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sounds very similar to my build then :good:

 

a build thread isn't just a must, it's the law here on the OC. Anyone doing an engine rebuild without a thread gets an instant ban :blum:

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