Solving my oil consumption While heads are off

[Azzman1000]

Hi all,

So, unfortunately I have to remove the head from the drivers side because the water jacket seal has given way. I knew this day would come sooner or later as I accidently damaged the seal when I did the heads about 5 years ago and I've relied on the sealant to hold up (which it has done really well)

The van has always had very poor oil consumption and the front drivers side cylinder (number 1 ??) is the culprit. I know, because I parked it up for a few months and when I went to drive it again it was only running on 3 cylinders. When I pulled the plugs #1 was so fouled it looked like it had been dipped in a bucket of black grease while the other 3 all looked reasonable.

I should note, once the engine is warm there is not much, if any visible smoke from the exhaust once it clears and there is a small oil leak from the rocker cover next to this spark plug port so oil is likely sitting on the top of the lug and making its way through the threads but not enough for the level of consumption.

My question is, where would the oil be getting into the cylinder ? 
Rings? - wouldn't it smoke badly under acceleration even when warm ?
Valves ? - Do they have rubber seals like the diesels do ? 

1985 1.9 ltr water-cooled DH engine.

Thanks.

******** EDIT ******
Just put 2 and 2 together, I replaced the expansion tank cap because the old one was stuck open, water would flow through without and pressure. Yesterday was the first drive since I changed it so I assume its the first time the system has actually built pressure which has caused the water jacket seal to go. Still need to sort the cause of the oil loss of course.
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[Syncro27]

Wow that seems to be quite a lot of oil on the ground under the van - assuming that is oil and not coolant.

That spark plug does not look like it has fired in anger for a long while and if the oil is getting all over the spark plug it will be going out the exhaust ports regularly.

Maybe when its running and warm you dont notice the smoke as much?

[Azzman1000]

Wow that seems to be quite a lot of oil on the ground under the van - assuming that is oil and not coolant.

That spark plug does not look like it has fired in anger for a long while and if the oil is getting all over the spark plug it will be going out the exhaust ports regularly.

Maybe when its running and warm you dont notice the smoke as much?

That's definitely coolant on the ground haha. the water jacket only gave way late last night and I parked it there overnight. 

The oil consumption had been a problem since I got the van on the road, I've just topped it up constantly. Now that I have to remove the head I should try and find the source of the consumption and see if I can fix it, considering it looks to be from the same side I need to remove. I originally was thinking its coming in through the valves because there is a bit or smoke on start up and a slight miss fire that all clears up once warm but I'm not sure

[Azzman1000]

I just removed the expansion tank cap and there was a lot of pressure in the system as soon as i loosened it there was a rush of air and coolant spraying out even though its cold 
(hasn't run since yesterday)

could it be an air lock ? would make sense that with the old cap it wasn't building pressure but now that it is the air lock could cause it to over pressurize ?

[Syncro27]

I just removed the expansion tank cap and there was a lot of pressure in the system as soon as i loosened it there was a rush of air and coolant spraying out even though its cold 
(hasn't run since yesterday)

could it be an air lock ? would make sense that with the old cap it wasn't building pressure but now that it is the air lock could cause it to over pressurize ?

The pressure in your coolant system is usually exhaust gas pressurising it. That would be one of the head gasket failure issues.

[Azzman1000]

The pressure in your coolant system is usually exhaust gas pressurising it. That would be one of the head gasket failure issues.

 Right, that makes sense. Just weird that it happened after changing the cap. Also I was trying to test it out today and bleed the coolant and the radiator never even got warm so I think the thermostat is stuck closed.

[luckyphil]

 Right, that makes sense. Just weird that it happened after changing the cap. Also I was trying to test it out today and bleed the coolant and the radiator never even got warm so I think the thermostat is stuck closed.

If the radiator is original it will most probably be clogged hence not heating up so needs replacement.  The pressure build up can be several things. Was the replacement cap new.  If so it should vent at aprox 15lb psi.  However as Scott said if exhaust gas is over pressurising the system then leaks quickly happen.  A healthy cooling system with no leaks should be evidenced by a completely full with no air at all in the pressure bottle.

[Azzman1000]

If the radiator is original it will most probably be clogged hence not heating up so needs replacement.  The pressure build up can be several things. Was the replacement cap new.  If so it should vent at aprox 15lb psi.  However as Scott said if exhaust gas is over pressurising the system then leaks quickly happen.  A healthy cooling system with no leaks should be evidenced by a completely full with no air at all in the pressure bottle.

Hi, yes I’m pretty sure it’s the original rad so quite likely could be clogged, also with the bleeder screw removed and the system hot I wasn’t able to get any air/water out the top so a blockage sounds likely.

The cap was a brand new “Blau” one, which from what I’ve read is one of the better ones. Just odd that I had no issues with the old one.

I’ve replaced head gaskets on both sides a few years ago and I’ve only done 4-5000 Ks on it so I’ll be suitably unimpressed if I’m getting combustion glasses in the system. Is there an easy way to test for this ?

Could a stuck thermostat cause coolant to overheat which would create that kind of pressure ?
Thanks

[luckyphil]

replace the radiator as it is an important component in keeping the engine cool.  I believe that a thermostat when it fails it fails in the open position

[Grantus]

replace the radiator as it is an important component in keeping the engine cool.  I believe that a thermostat when it fails it fails in the open position

Agree with the radiator replacement, as they do event get clogged, and fail.

Not VW, but we had a thermostat fail in the SAAB in the closed position. Remedy was to let it cool down, and remove the thermostat to get it home, and order a replacement.