Riddle me this: Headgasket or not..

[Bovien 6]

So, I have a XU only starting on 3 cylinders, getting the 4th running after 20 sec or so with some speeder daps. Last time this happened, it was the head gasket, which I had replaced along with a renovation of the head. 
Car has run 5-10.000 km since. 

Now I'm there again, but have also checked the following, which all point to no HG issue:

 

• Compression test is good
• Pressure test of the cooling system is good
• No white smoke from exhaust except at startup
• I've tried a coolant combustion leak tester, but doing this from the expansion tank is a bit bothersome. Seems there are aboslutly no gas escaping through there, so no bubbles in the fluid test container and no change of color. 

 

But I am loosing quite a bit of coolant. At startup, I get a lot of burnt coolant smoke from the manifold/exhaust donut. How can coolant end up there? And what else can be the reason for the last cylinder not catching on? If fairly sure it is not ignition cables or plugs as these has been replaced. 

 

I was thinking about tightening the head bolts a bit more, but if I have no HG issue, that would not help the situation. 

[Tom Fenton 1,542]

Check inlet manifold gasket first.

[Bovien 6]

Thanks! Guessing that is just replace, no real way to check. 

Looked it up, and as far as I can see, it is NFP in servicebox.

So bought two others. One looks like the OEM, but is really cheap. The other more expensive, but comes as two parts. 

 

I see your point, internal leak of coolant into cylinder would result in exactly what I see. 

Hope things come apart without to much of a hassle. 

[Bovien 6]

So, that didn't help. Think it made it slightly better at startup, and I can see the old gasket was failing around the water canals. 

But I the car still only starts on 3 cylinders for 5 seconds or so. 

 

Tried to measure for exhaust gas in the coolant, but the kit I bought was for use in a radiator cap and not through the expansion tank the 205 has. 

Made it fit, and the test was negative, but again, there were no real gas pressure buildup to push anything their the test tube.

 

Any thoughts on how I can diagnose the issue???

[DamirGTI 342]

Tried the chemical test on hot or cold engine ?

 

From my personal experience with an chemical block tester , it is quick and precise .. if there is an problem , it'll "react" (change fluid colour) .. try first on a cold engine , and then on a fully warmed up .. as you might have an crack somewhere in the head or the liner which seals/closes up as the engine starts to warm up .. and always use fresh tester fluid , throw away used one and fill up with new/fresh (often times it gets contaminated with the antifreeze , thus i always empty the expansion bottle almost down to the bottom or flush the antifreeze coolant mixture out and fill up the system with plain water for testing purpose)

 

D

[Bovien 6]

Did exactly that. No change in colour, but also no visible bubbles through the fluid.

However, found a tiny bit of 'mayo' in the top of the oil filter cover today... 

[DamirGTI 342]

Some "mayo" in the oil filler is nothing to worry about , it happens if you don't drive the car regularly/daily , if the air humidity is high , and if you drive it only on a short trip where the engine doesn't have a chance to warm up completely to burn off the condensed water (and excess fuel too) from the oil .

 

Do you still loosing coolant after the inlet manifold gasket replacement ? also , still have white "sweet smell" exhaust smoke ?

 

 

D

[Bovien 6]

No mentionable loss of coolant (yay!) But still a bit of smell while driving through the interior air vent. No smoke from exhaust. 

Seems like I had a change at startup with the one cylinder after the gasket change, but hard to tell...

 

The car only needs to be stopped for few mins before the issue shows again 

 

[DamirGTI 342]

At least , seems like you've found the source of the leak i.e. inlet manifold gasket .. if the coolant level is now stable and there's no smoke from the exhaust .

 

Coolant smell which you can sense inside , can be leftover from the repaired leak (liquid trapped around the block webs tend to need quite amount of time to dry out/evaporate) or you might have an leaky expansion bottle cap .

 

Anyhow , if you suspect that the inlet manifold gasket repair didn't seal up 100% , i'd be tempted to torque up all the manifold bolts by say 1/4 of a turn .. and see what happens .

 

Then , i'd replace the spark plugs (might be "coolant fouled") and go to an good hour or two drive around .

 

D

[Bovien 6]

Thanks for your input 

Just put it in storage for the winter. Will be done time till I get to it again. I'll try to torque them a bit more and replace plugs and report, as soon as I get to it. 

 

Annoying that it's so hard to get down there. I had no way of getting my torque wrench to fit. I tightened them up l quite nice with a 1/4" wrench without pushing to much. Torque figures for the nuts are not a lot as far as I remember. Fluid ran out the first time I tightened them up. Second time m was good, but yeah, could still be leaking a bit

[DamirGTI 342]

Yes , there's not much space for torque wrench around there .. i have an small one which does up to 20-30Nm maxi and with couple extensions it's doable , with an big torque wrench - no .

 

I usually pre-coat the gasket with either liquid "hermetic" resin , or anaerobic sealant .. as most of the aftermarket inlet manifold gasket do not have any sealant applied on whilst the OE gasket does (kinda same as on the head gaskets) .

 

A bit crappy picture , but you'll get the idea :

 

 

D

 

[Bovien 6]

Sweet! With a try next time I get my hands on it. 

Amazing it can be so hard to diagnose a head gasket (even though this likely is the manifold gasket playing up. 

 

The pic you posted looks exactly like the one I got. It's easy to get to as I found you only need to loosen the manifold and not regime it entirely as per Haynes. 

 

I'll get it sealed up to remove all doubts

 

Thanks a bunch, mate!

 

Edited October 7, 2018 by Bovien

[DamirGTI 342]

... or , you can even plug up the two coolant holes on the head/manifold gasket base with an grub screws and be done with it ! as they're not needed on a GTi .

 

Check the Tom's 1.6 turbo build thread and you'll see how to plug up those holes if you want to go that route .

 

D

[Bovien 6]

Yup, seen that. I'll try the other way around. If that fixed it, I can manage to do that every X years.

[DamirGTI 342]

For what i can say , i really never had such issue .. i did however had air leaks years ago by using aftermarket gaskets dry , but from then on i always have practice to pre-coat the gasket lightly with sealant (but not the RTV sealant !) and no leaks what so ever for years of engine use and abuse !!

 

D

[Bovien 6]

Ok, so I got the car back from storage. Seems it burns more coolant at startup than before storage. It has not been started over the winter..

 

Today I pulled the plugs and could see water in cylinder 3. Just a bit on the back side. I pressurized the coolant system and slowly water was dripping (!) into the back of the cylinder from the to. 
Does anyone know where it can drip from? In case of headgasket, I would assume water would creep in and flow down the cylinder wall. This was a drip from up top. Would this rule head gasket out or not?

 

Also, after pulling the plugs and pressurizing the system, it won't start. Starter runs fine.. What's up with that. Weird little car. Back to spark, air and fuel. It should be getting all so really don't see what could be messed up here. I'll leave it a bit and see if it will fire up...

[dt_ 7]

If you are looking down the plug holes by eye it might be difficult to see exactly where it's coming from.  The water might be beading up on the lightly oiled cylinder wall and 'rolling' down which may look like a drip, or maybe the head is cracked slightly higher up