What's My Problem? Please advise

[suzublu]

Originally Posted by T-Cut

My 1.8T recently dumped the coolant into the sump. It wasn't overheated or stressed, it simply happened. Prior to that, I'd been topping it up with a cupful of coolant every couple of weeks. I knew something was wrong, but it happened before I'd a chance to work on it.

The problem was the OEM elastomer head gasket. The 'rubber' seals around the oil channels had simply delaminated from the metal. The fire rings were perfect.



With this sort of failure, you don't get pressurisation in the cooling system. It's very insidious because there are few outward signs. Mayo under the oil filler cap is one as is steam being emitted from the open oil filler neck when the hot engine's running. Cold weather is best for this test.

I replaced the gasket with the latest elastomer type from DMGRS.

TC

Exactly the same symptoms as mine last February, caused by my stat failure

[marinabrian]

Originally Posted by suzublu

Exactly the same symptoms as mine last February, caused by the use of OAT antifreeze

Yep, seen that on more than one occasion too

Brian

[suzublu]

Originally Posted by marinabrian

Yep, seen that on more than one occasion too

Brian

Ooh you naughty boy

[aReallyNiceCar]

If there's no back pressure in the water system, it's always possible you've just got an external leak somewhere.?
A bit of 'mayo' at the filler cap can be a sign of condensation, especially if the car doesn't get used a lot, or does a lot of short journeys where any moisture doesn't get the chance to 'boil-off'.?

[T-Cut]

On the next cold, preferably frosty morning, run the engine till it's at 'normal' temperature and open the oil filler cap while it's ticking over. Look for steam being pumped out. If the volume of coolant you're losing is getting into the sump, it will be pretty obvious from the steam. The dipstick may not show a creamy emulsion/mayo appearance. Standard 50% EG coolant can produce a tight, viscous emulsion that doesn't look that abnormal on the stick. The crankshaft activity homogenises the mix to a stable inseparable mixture. Also note that the cooling system doesn't necessarily over-pressurise if the head gasket fails. It depends on how it fails.



TC

[billh]

Hello again,
thanks to all for pointers. Went for a bit of a run today, on return opened the oil filler cap with engine running and hot. So , steady jet of steam blowing out the filler with some water(!) droplets thrown out . looks like T-Cut is on it, head gasket needed. I think it was done once before I had the car about 12 years ago so it hasn't done too badly. Do I need to replace head bolts, oil rail etc as well?

[DMGRS]

While avoiding the OAT antifreeze argument, it sounds fairly definitive that you do have HGF.
First of all, I'd read this guide we wrote with regards to choosing between the MLS and Elastomer gasket:
https://www.dmgrs.co.uk/pages/choosi...ead-gasket-kit

There's a good argument for both gaskets, but truth be told these days we sell more of the Elastomer gaskets than the MLS by a ratio of around 5:1 - most of the mobile mechanics we sell to also prefer the Elastomer item.

With regards to the rest of the job, it's a case of changing what you can afford - in a perfect world the whole shebang would be changed; but it'll be of no massive consequence if you have to forego the oil rail and fresh bolts (providing yours are in spec).
I'd do the cambelt, tensioner and waterpump while it's all apart though - we have an all-metal cambelt tensioner that replaces the original plastic item, and is included as standard with our kits.

To give you an idea of pricing, this is our most popular kit at the moment:
https://www.dmgrs.co.uk/collections/...e-k-series-all

Good luck!

[T-Cut]

Originally Posted by billh

Do I need to replace head bolts, oil rail etc as well?

The uprated oil rail was introduced to accompany the MLS gasket system, which needs torquing down more than the elastomer. When I did mine, I fitted DMGRS' elastomer and re-used the head bolts. I did have the head minimally skimmed to provide a perfect surface. They didn't take more than a thou off by the look. The old bolts can be checked for length to make sure they've not stretched into the plastic state. Default bolt lengths are on record and will be OK with the old oil rail. That's the minimalist approach that most owners take. If you feel happier with new bolts and oil rail, well you're paying for your choice. It's all pretty straight forward, but you'll need it lifted safely to a workable height to replace the oil rail.

We'll all be interested to see the old gasket when you've finished. Good luck.

TC

[billh]

Head gasket gone same as T-Cut's, elastomer in pieces round the oilways. A lot of mayo lower down engine, what's the best way to clean this, will I really have to remove sump?
Also, I just typed a longer message but the system logged me out and the message was lost. How to avoid this?

[T-Cut]

I would fit the Payen or its equivalent elastomer gasket and use the old bolts. I personally wouldn't touch an MLS/oil rail/uprated bolts fix myself. By default, the job requires a new water pump and timing belt/tensioner. Follow Haynes and you'll not go wrong. When that's done, refill with your preferred coolant, then clean out the oil system.

Get a gallon of SAE 30 flushing oil and some Wynn's engine flush. Fit a cheap oil filter. Run both (I gave mine several times up to running temperature) or as instructed on the tin. Drain down and refill with ACEA A3 diesel engine oil and drive on that for a few hundred miles to scour out what the flushings may have left. Replace the diesel oil with your favourite stuff plus your preferred oil filter and it will be back to how it used to be.

TC