Still working on the MK2... getting there slowly but surely

Its a 1.2 8v. When i got the car i knew there were a few faults to sort... now ive come to the coolant. What happens is this... when i start the car, there is a huge pressure build up in the expansion tank. when i got the car it had very little coolant in it, but ive no idea how long it had been run like this tho.

So i drained and flushed the system, put new coolant in and bled it, then started the engine. within a couple of seconds, coolant was blasting out the filler cap, so i stopped the car and had a look on the forum read about possible thermostat and/or headgasket. I doubted the head gasket as when i first got the car it had an ICV fault which was revving the engine like mad - wouldn't have expected that with a blown HG. And once the ICV was sorted, it ran fine (bar coolant obviously.) So i drained the system into a bucket (no sign of oil in it) and replaced the thermostat. I also swaped the filler cap with a known good one from my other MK2. Refilled and bled, then started it up again. Exact same problem - coolant blasting out of the filler cap. I had disconnected coils so i could see if the symptoms were the same just cranking it over and they were.

Completely lost for ideas now... any suggestions before i start with the HG (only other possibility i can think of)?

why do people always think because oil and water hasn't mixed the gasket is fine? if gasket has only gone between a water way and cylinder no oil and water will mix, you will just get what you describe above

dave said:

why do people always think because oil and water hasn't mixed the gasket is fine? if gasket has only gone between a water way and cylinder no oil and water will mix, you will just get what you describe above

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yeh i know oil and water don't necessarily need to mix to show the symptoms, but i was suprised the car would still rev to 5k with a blown HG
is there any test i can do to prove a HG failure in this situation? if it is HG and i did it myself, how much should i expect to pay for head skimming?

£30-£45

and you can get a shiff test to confirm

cool, thats a lot cheaper than i expected

where would i go for head skimming- just a metalwork engineers or something? anyone know anywhere near leeds/bradford that do head skimming?

yeah engineers shop, look in yellow pages there be loads

dave said:

why do people always think because oil and water hasn't mixed the gasket is fine? if gasket has only gone between a water way and cylinder no oil and water will mix, you will just get what you describe above

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i can't understand this either
unless of course you spend any amount of time around a rover

they mix it into a right good cream every time

but overall mixing is one of the least seen symptoms

if its your head gasket you should be able to get a sniffer test done at any decent garage, we have one and there very handy for this, you put it in the coolant bottle and if theres gases from the cylinders (indicating HG failure) then the fluid inside it will change colour, other things to look for is gunk under the oil cap, any signs of leakage around the head gasket area,., also are you sure you bled it correctly?

thanks for the suggestion vtec, but ive confirmd head gasket now. just been in the garage removing the exhaust manifold and it was like removing a wastepipe from a sink coolant everywhere.

So i went ahead and started removing inlet, aux drivebelt/pully, engine mount, timing cover, rocker cover etc... FINALLY got the head off and all four pistons had pools of coolant on them which i thought was weird... id have expected only one or maybe two to have coolant on them???
having said that, some of the head bolts were really stiff but others relatively easy to remove, so it may be that the head wasnt sat flush, allowing the leak to all four.
anyway... on inspecting the gasket, there were no signs of cracks etc, but there is soot inbetween cylinders 1+2 and between 3+4. the bit that concerns me is that the soot is on the underside of the gasket (i.e. block side) so is skimming the head going to work in this case?

Wot a lot of talk about an obvious problem.
BTW the bolts are stretch type ie they are tightened up to a stretched state.
If the head gets overheated ali expands further than steel abd stretches the bolts beyond their elastic limit, consequently when it cools the bolts are looser.
The fact that soot is on a suface means that a burnt gas went over it, it does not mean that it has burnt the surface away.
Particular attention should be made to the width of the land between no 4 cylinder and water jacket hole, the ali can rot away at this point.
If its rather narrow then it needs filling with weld.
The engineering shop will put you right on that.

reddy4bed said:

Wot a lot of talk about an obvious problem.

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yeh i knew it was probably HG, but i just wanted to make sure there were no other easier (and cheaper) possible faults.

BTW the bolts are stretch type ie they are tightened up to a stretched state.
If the head gets overheated ali expands further than steel abd stretches the bolts beyond their elastic limit, consequently when it cools the bolts are looser..

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that would explain why coolant was able to reach all pistons then

Particular attention should be made to the width of the land between no 4 cylinder and water jacket hole, the ali can rot away at this point.
If its rather narrow then it needs filling with weld.
The engineering shop will put you right on that.

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thanks for the tip... had a look and tbh the whole head looks in good nick but ill have the engineer give me his opinion just to be on the safe side.

Got a quote today for £25 from an engine reconditioning place near here he said just to clean it up and make sure the rocker side of the head is completely flat so he can just stick it straight on the machine.

any advice on what to use to clean the crap off it?
also removed camshaft but theres bits of tube for locating the camshaft bearing caps which are protruding and dont seem to want to come out. how do you remove them?

you dont, he should be able to use blocks to sit it on

cool.

what about cleaning it, any tips on what to use? I heard petrol was supposed to be good for eating away all the muck, but i gave it a go with a dab on a rag an it'll take me all night at this rate!

Xen said:

cool.

what about cleaning it, any tips on what to use? I heard petrol was supposed to be good for eating away all the muck, but i gave it a go with a dab on a rag an it'll take me all night at this rate!

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gunk engine cleaner and a tooth brush

they often come back from machine shop already clean

indeed, place i get mine done at - i just take the head in as is, and it comes back skimmed and nice and clean, all for £25. bonza!

well it looks like it'll have to go as is then i dont have any of that cleaning stuff and i want to drop it off tomorrow before work... i only have about a week to get it running properly and MOT'd so i really need it done ASAP.

ok its skimmed and ive got all my bits... HG set, bolts, new timing belt and tensioner, got a new water pump aswell as it was only £16 and the old ones looking a bit worse for wear... best do it now rather than wait for it to fail.

in this HG set there seems to be 2 rocker cover seals tho both very similar, but one has two narrow grooves all around the underside, and the other just one groove. why the difference and which should i use?

also, may sound a dumb question but which way does the shaft move? there are arrows on the new timing belt so looking at the engine from above, do the arrows want to be facing towards the front or rear of the car?

yeah front of car, dunno the other one, never got 2 before

turns out i needed the two groove one... the single groove one looks like it was designed to fit over a lip or something.

anyway back to the progress, or lack of. im really getting sick of this car now - wish id have just gone for an engine swap in the first place

so HG was fitted, aswell as all the other new parts (bar the waterpump, as the existing one seems fine and im on a budget.) filled with coolant and started it up....

1) theres a fairly loud sound coming from the oil breather like air rushing past

2) the car will start most times, then really struggle others - just turning it off and back on always cures it tho. (car runs smoothly once started tho)

3) i had drips of liquid coming from the connection between the cat and flex pipe. it was black but very thin (i.e. not oil.) when i turned off the car and seperated the joint, there was a loud, low toned humming noise coming from the cat that lasted about a minute. when i started the car for a few seconds with the joint disconnected, more black drips. Coolant level doesnt appear to have changed tho.

what the hell is going on? im all outta ideas... whats the liquid? why the low toned humming noise, and whats that noise coming from the breather?

my only assumption is that the new HG is still leaking