Overheating

Anything else related to the Stage 1 V8
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firemanshort
Posts: 378
Joined: Fri Feb 10, 2006 2:42 pm
Location: Loudoun County, VA - near Wash DC

Overheating

Post by firemanshort »

I packed up my truck with the intention of driving 8 hours from the Washington DC area to the southern coast of North Carolina to catch a ferry out to Portsmouth Island on the Outer Banks to do a little camping with a group of Land Rover buddies. I got as far as 2 hours from my house and had to stop - the truck kept overheating - badly.

Luckily, I stopped in Richmond, VA where a good friend runs an independent Land Rover repair shop. He is the same person that helped me with my recent frame swap. We worked on it for a full day and got nowhere to solving the problem. Trip canceled. Not happy.

It runs for a short while and seems ok. When I drive at highway speeds, it appears the coolant is being forced out the expansion overflow tube until I get so low on coolant that the motor overheats. We replaced expansion tank cap and thermostat and that did not help. We did a pressure test on the whole system and could find no leaks. The water pump is new, a Britpart, and I took it back off and gave it a thorough visual inspection looking for loose impellers or other signs of fault and found nothing out of the ordinary. We are not seeing any white smoke / steam from the exhaust and it does not smell of coolant. The engine runs fine with great power and no miss. Still - I think we might have a head gasket issue. We are still looking into this so the answer is still yet to come.

If anyone else has experienced this then please share your knowledge. I will update the thread once I get some more testing done and finally pinpoint the problem.
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Firemanshort
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Virginia, USA
disco2hse
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Location: Auckland NZ

Re: Overheating

Post by disco2hse »

Changing the thermostat generally will not make the car run cooler since it only provides increased temperature for when running cold.

If the water system is pressurising, that suggests head gasket. However, I would think it is more likely to be blocked galleries or the radiator. Try engine flush to see of that makes any difference and get the radiator rodded out.
Alan

1983 ex-army FFR 109 Stage 1
2005 Disco 2 HSE TD5
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Geoff
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Location: Leicester UK

Re: Overheating

Post by Geoff »

Assuming no trapped air in the system blocking the flow, I agree with disco2hse - what state's your radiator in? I had a persistent overheating problem a few years back and swapped everything and borrowed a special thermometer to measure the temperature across the radiator, but it wasn't until it started leaking that it became apparent the state it was in. Fitted a new rad and all was fine (once I'd rid the system of the inevitable air bubbles :) )
2 1981 Stage One 109 V8 SWs
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firemanshort
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Location: Loudoun County, VA - near Wash DC

Re: Overheating

Post by firemanshort »

My radiator is 6 years old. I used a temp gun and saw a reliable 20oF drop accross the core when running at temp.
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Firemanshort
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Virginia, USA
disco2hse
Posts: 1637
Joined: Sun Apr 27, 2008 3:51 am
Location: Auckland NZ

Re: Overheating

Post by disco2hse »

Galleries then? These engines are known for that. What kind of coolant are you using and did you mix it (I recall quite a discussion on AULRO some time ago about some types being bad for the metals in the V8) ?

Have you checked the timing too? Is it too advanced?
Alan

1983 ex-army FFR 109 Stage 1
2005 Disco 2 HSE TD5
Alicerover
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Joined: Wed Nov 16, 2011 10:34 pm
Location: Leicestershire

Re: Overheating

Post by Alicerover »

Sorry to hear about your woes :(
As my father in law tells every customer of his, there are two things that will kill a V8. Lack of oil and excessive heat, the blocks do not like to get hot at all.
I would suspect that you do have a head gasket problem causing excessive pressure in the cooling system. I'm affriad that it sounds like some serious work to be done, when you get the heads off, they will need to be skimmed to ensure they are flat and refit using a good quality gasket. The original gaskets are prone to leak, the modern replacement is much better.
It would be worth getting the rad checked out, when I was rebuilding Alice, I had a thicker core put into the rad and I run a 65 deg thermostat. Alice runs at 70 deg according to my direct reading temp guage.
The V8's start to loose significant power at temps over 85 deg and the under bonnet temps can rise sharply causing other problems like fuel vaporisation.
Hope you get it sorted soon
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