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[griff2494]

right after the reply to the thread saying even with that much mayo does not mean its the hg could just be short journeys and to no for sure i need to do the comp test!

got all my warm kit on again and went to do it
this is my tester (you will no better than me,wot the readings should be and also bars or psi)


right all plugs out,and electrics disconneted

pot 1


pot 2


pot 3


and the dreaded pot 4

can see it better here

 :-? :-? :-? :-? :-? :-? :-? :-? :-? :-/ :-/ :-/

they all look the same to me !!!!!! is the pressure on all pots what it should be ??

but i did also find this,could this have some thing to do with it??



i noticed that the curd stuff is WET!

[tunnie]

as long as they are all the same, thats good news! Checked the HBV?

[griff2494]

apart from running my hand around the hbv how can i check it?
is there some kind of test you can do?

also seeing the comp on all 4 pots are the same at 15bar what could the bubbling in the header tank i was getting be???
the pipe from top of rad going to thermostat seems to get very hard with presure as well  could the thermostste be blocked/not opening because of all that crud i showed in the pictures? also could that be where the coolant is leaking from

[Abiton]

What temperature was the engine when you did the above compression test?

I'm thinking you may need to do it both cold and hot, as if it is a fire-ring leak, it may only leak detectably at some temperatures, due to thermal expansion differentials.

I prefer the simple test of running the engine up to temperature, leaving it to cool back down for a few hours, then looking down the sparkplug holes with the aid of a bright little torch.  If there's coolant sitting on any of the piston crowns, you have a HG problem. If there isn't, you probably haven't.

Do the bubbles in the expansion tank smell of fuel or exhaust fumes?

[griff2494]

hi there

yes the bubbles did smell of exhaust ,and the exhaust its self seems to be kicking lots of steam out, as for comp test the engine was at normal running temp

but now the bubbles in the header seem to have stopped  :-/

i thought the bubbles prob ment hgf esp with the mayo in the pipes as well ,but would the comp test not shown this up???

and for there to be no oil/water mix in the header or engine block where could the hg of gone?

[Abiton]

If a fire-ring (the metal rings that are part of the HG) isn't sealing 100% against the head and block, at all temperatures, you'll get combustion products at very high pressure leaking into the coolant when the engine is running.  Because the pressures are so high during combustion, if the fire-rings don't contain all the gases, they will surely get past the fibre parts of the gasket and most-likely find their way into a coolant channel.

When the engine is turned off, the residual pressure in the coolant system may force coolant the other way through the non-sealing area, and ending up on the piston crown of the affected cylinder.  The piston-ring seals are almost certainly good enough that any such leaked coolant will sit on top of the piston for a long time rather than draining down into the sump.
So - no coolant shows in the oil.

Oil in the coolant is only really associated with oil-cooler failure on the Omega, and I don't think any of the 4-pot variants have one.

[griff2494]

ermmmm i wish i could 100% say it is hg or not ,like i say the bubbles have stopped now, i want to get the car 100% fixed as the car is lovely and i dont want to kill it,

BUT on the other hand i dont want to spend loads of money and my time doing the hg if thats not the prob esp seeing it xmas soon

[Abiton]

So, do the "look down the sparkplug holes" check I suggested. 

The only other way that I can think of for exhaust fumes to be getting into the coolant is a crack in the head.  Much less likely than a fire-ring problem, IMHO.

Here's a piccy of a gasket, showing the shiny-metal fire-rings.  Note how adjacent the cylinder-4 one is to the big rectangular coolant channel at the end. 



Unfortunately, this seems to be a weakness on the 4-pot (2.0/2.2) design.  If coolant flow up that channel is reduced, by for instance a clogged heater matrix (that channel heads out the back of the head towards the HBV/matrix), there may be local overheating of block and head in this region, making a failure more likely of this firering seal. 

[PhilRich]

Hi Griff, firstly yes you do have a longstanding coolant leak from the thermostat hose, so drain off the coolant via the radiator drain plug (round red knurled handle on bottom right hand side of rad, can be seen by looking up from beneath the front bumper). If the coolant is new or very recent, then drain it in a clean dish for re-use. Remove the offending hose from the thermostat housing, push a clean rag into the hole to stop any crap getting in there & scrape off the crud & rub down with emery cloth or sand paper, little bit of lubricant & back on with the  hose. Refill the system with coolant (should be a 50/50 mix) & run the engine up to temperature with the expansion bottle top off, 'burping' the coolant hoses (top & bottom hose) several times as the engine gets to temperature, then refit the expansion bottle cap & keep an eye on the coolant level in the bottle for a few days. You may need to 'burp' the hoses a few more times over a couple of days.






Secondly, from my experience the bubbles in the expansion tank are an early indicator that the head gasket is failing & this is undoubtedly due to poor coolant maintenance in the past. If yours does as mine did, then the next thing will be rough running at cold startup with very noticeable coolant loss & clouds of water vapour out of the exhaust 
Do as Abiton says & whip out the plugs after the car has stood overnight (no. 4, nearest the bulkhead would be my first choice), then either shine a torch into the cylinder to see if there is any liquid on the piston crown (it can only be coolant) or use a cotton bud or similar firmly taped to a stick/screwdriver or whatever & lower it into the bore until it touches the piston crown, moving it from side to side to ensure you reach the hollow in the crown & check for wetness in each cylinder & as said earlier try no. 4 first, it may save you having to do the others!

Thirdly, to check the HBV, first find it!, it lives against the bulkhead, low down on the drivers side of the engine bay just below & to the right of the brake servo drum. Run the engine up to temperature, shine a bright light on the HBV & check for signs of old leakage (similar to your thermostat!), then set the heating to high on auto (air con running) & check the HBV again for leaks. Lastly, pull the thin vacuum pipe elbow off the top of the HBV & block the elbow with a small bolt/screw to seal it, then change the heat settings from hot to cold, auto to eco & back again & recheck for leaks on the HBV. When finished don't forget to unblock the vacuum elbow & replace it firmly back on the top of the HBV. Sorry this so long winded but I don't know how much knowledge of the car you have/haven't mate, so i'm not trying to teach you to suck eggs

[griff2494]

thank you mate

i will try all the above on tues (im on earlies so have a hr in the afternoon :-) )

i have quite a bit knowledge on rovers and classic minis but thats me lol,so any info on this car is top stuff i really thank everyone thats replied and is helping me fix this problem :-)

i had a 1996 omega years ago and was best car ive ever had (well apart from my toy lol my classic mini which ive dropped a 1.8 vvc engine into)

once again thanks for everyones help

i assume on that plug on rad for drainage i can connect a hose or something like to it so dont need a bucket right under the car

if anyone is interested heres a link to my classic mini build (hope this is allowed on this forum? if not someone please pm me and i will remove the link)

http://www.16vminiclub.com/forums/showthread.php?t=6478

cheers
griff