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Old 1st August 2020, 17:10   #1
Mogmike
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Default Coolant in oil after head gasket blown.. Any thoughts on main cause?

Hi .. I have the dreaded head gasket blown at 56k miles on my 2004 Rover 75 1.8 petrol engine. I'm about to take the head off and check the liner height as recommended on the site here before buying the full kit to change everything. My question is that all the coolant has gone into the engine and formed a thick coffee solution in the sump. The rad and water hoses are empty. Doe this point to any particular part failing..? Other than the head gasket itself.. Obviously I will be changing the water pump, thermostat plus the cambelt and shall check the head and inlet manifold for any distortion.
I would welcome any thoughts and comments.. Many thanks... Mike
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Old 1st August 2020, 17:45   #2
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Hard to tell - the HG may fail when stressed by heat - so did you have a temperature event(s) or losing coolant prior to the "mayo" forming - if so could be leaking coolant hose, a classic failure point being the plastic t -piece behind top left on the RAD or failed water pump.

If no temperature event then some posit that Orange OAT coolant has a weakening effect on the gasket - research the posts on here and draw your own conclusions - I have looked at the debate and as a consequence use non OAT blue coolant in may car for the last 4 years.
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Old 1st August 2020, 19:38   #3
Rich in Vancouver
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I feel your pain!
In my case it was one of the HG silicone tracks that went.
Liner heights were OK so I used one of the SAIC gaskets and
it is still going strong several years later.

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Old 1st August 2020, 20:27   #4
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Exactly like Rich in Vancouver, I had the classic original elastomer failure. There had been small coolant losses for a few weeks but there was never an overheating event. It just happened. A lot of the coolant was dumped into the sump. I wasn't many miles from home and managed to limp it back. The coolant/oil mixture formed a viscous black liquid resembling tar.




Was it the 50% OAT that finally broke the elastomer adhesion? I dunno. I replaced it with the Payen elastomer type. No way would I consider the MLS solution.

EDIT: 2004 1.8 Turbo 34,000 miles

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Old 1st August 2020, 20:30   #5
suzublu
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Quote:
Originally Posted by T-Cut View Post
Exactly like Rich in Vancouver, I had the classic original elastomer failure. There had been small coolant losses for a few weeks but there was never an overheating event. It just happened. A lot of the coolant was dumped into the sump. I wasn't many miles from home and managed to limp it back. The coolant/oil mixture formed a viscous black liquid resembling tar.




Was it the 50% OAT that finally broke the elastomer adhesion? I dunno. I replaced it with the Payen elastomer type. No way would I consider the MLS solution.

EDIT: 2004 1.8 Turbo




TC
Exactly the same as mine
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Old 2nd August 2020, 16:05   #6
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From my experience and reports from others, if OAT is truly the cause, then these gaskets were never fit for purpose. I think I'll do a compatibility test on the OEM elastomer to see whether 50% OAT does actually affect it over time.



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Old 2nd August 2020, 17:43   #7
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Is it not the case the reason OAT was specified was that it requires only a 5 yearly change as opposed to say blucol which is 2 yearly and was primarily done to get the company car market.
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Old 3rd August 2020, 16:59   #8
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Quote:
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Is it not the case the reason OAT was specified was - - - - -
Probably. But did MGR assume their particular gasket was resistant without testing it? My head had pink-coloured staining around the failed beads, but nowhere else.



The prevalence of HGF in the K16 suggests that adhesion failure of the elastomer beads is the underlying cause. MGR introduced the PRT system to the K16 specifically to mitigate against thermal gradients that were said to be the crux of the problem. Yet the PRT engines continued to have HGF. As illustrated above, many failed gaskets have fully functional fire rings. Nowadays, OAT type antifreeze is the most commonly specified and today's elastomer gaskets are tolerant.

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