Nodge68 · Nov 26, 2015

comdek said:
I think the problem is the HGF. I opened the reservoir now the night and saw a small smoke with exhaust smell.
B34R said about the sniff test, but I got it wrong because of translation into Portuguese.

I will buy a transparent hose and will change the output of the intake manifold. So I´ll see which cylinder head is leaking compression gas. If confirmed, this weekend I´ll remove both cylinder heads to change de head gaskets.

Just to warn you. Doing the KV6 head gaskets with the engine in the car is a really difficult job. The front head isn't to bad but the rear one is a swine. These limited access to the exhaust manifold nuts. The head is awkward to refit as you can't see where it locates. Last KV6 heads I did, I removed the engine to make life easier.
Good luck

zefrench · Nov 26, 2015

I would look at each spark plug before doing the heads, and do all these:
a leakdown test
a compression test

Report the results.

Now did you say you did the chemical test that shows the presence of combusion gas by using a liquid that usually goes from blue to yellow or green? Did you try it with high RPM that cause the engine to rise in temperature?

zefrench · Nov 27, 2015

Also since the engine is a liner engine, make absolutely sure not to move the crankshaft with the engine head off. If you move the crankshaft with the heads off, the liners will move.

Have you looked at the front three sparkplugs to see any difference ?

comdek · Dec 4, 2015

I make some tests changing the top hoses to a transparent hose. In front cylinder head, a lot of bubbles come out to reservoir.

I don´t have the compression tester, but try to find a one. The chemical test I not finding to sell here.

Tomorrow I´ll remove the front sparkplugs to see if there a evidence that have water inside of cylinder.

comdek · Dec 8, 2015

Today after removed all coolant, removed the intake manifold and pressurized the system, found a leak in cylinder 5. Now this must be the problem.

The front head is easy to remove but rear is more dificult. I´ll release the engine a bit down to remove the exaust bolts, underneath is hard to access because of the IRD in front.

zefrench · Dec 8, 2015

comdek said:
Today after removed all coolant, removed the intake manifold and pressurized the system, found a leak in cylinder 5. Now this must be the problem.

The front head is easy to remove but rear is more dificult. I´ll release the engine a bit down to remove the exaust bolts, underneath is hard to access because of the IRD in front.

Very neat test. what is that tester? Just an air regulator connector to the cooling system and running roughly 12 psi ? Is that it ?

comdek · Dec 8, 2015

zefrench said:
Very neat test. what is that tester? Just an air regulator connector to the cooling system and running roughly 12 psi ? Is that it ?

Yes.

comdek · Dec 9, 2015

After a bit work, removed the front cylinder head. Found a coolant fluid in cylinder 5, as expected.

Nodge68 · Dec 10, 2015

Looks like just a clean up and gasket change will sort you out. Remember DON'T TURN THE CRANK while the heads of off and clean the tops of the liners carefully, so you don't disturb them

comdek · Dec 10, 2015

I caught crankshaft with pinlock. Tomorrow I will try to remove the rear head disconnecting the underneath mount and pull the engine forward

zefrench · Dec 10, 2015

Nodge68 said:
Looks like just a clean up and gasket change will sort you out. Remember DON'T TURN THE CRANK while the heads of off and clean the tops of the liners carefully, so you don't disturb them

Hi Nodge68. Any ideas if the cylinder liner (5 in this case) needs to have its lip cleaned up somehow? What if it is rusted on the lip? Taking a liner out and using blue hylomar does not appear like fun from what I saw.

A nice thread on liners on the 4 cylinder engine, I would think the same principle apply: http://www.the75andztclub.co.uk/forum/showthread.php?t=146867

Nodge68 · Dec 11, 2015

zefrench said:
Hi Nodge68. Any ideas if the cylinder liner (5 in this case) needs to have its lip cleaned up somehow? What if it is rusted on the lip? Taking a liner out and using blue hylomar does not appear like fun from what I saw.

A nice thread on liners on the 4 cylinder engine, I would think the same principle apply: http://www.the75andztclub.co.uk/forum/showthread.php?t=146867

In a perfect world, liner 5 could do with being replaced. However this adds a huge amount of work and time to affect a repair. In this case I would clean the liner top carefully, check liner hights then rebuild the engine using new gaskets. I suspect that the problem was caused by a faulty gasket from new or lack of a corrosion inhibiting coolant. I think in this case, the gasket will work to repair the engine.

Nodge68 · Dec 11, 2015

The gaskets used for the KV6 head has a heat activated sealant on the surface. This is very effective at sealing imperfections on the mating faces. So I think you will be ok.
If you are worried then it is possible to change the liner. You need to bear in mind that the lower block needs removing to access the rod bolts. This is best done with the engine removed from the vehicle.

comdek · Dec 11, 2015

Tomorrow I´ll remove rear head and check if both is flat. If not, I'll send to skimming.
I will not change liners because they are expensive in my country, and I don´t have necessary tools to remove the piston and rings. The cost for repair this engine here is very high because the need to import parts (import fee, shipping, customs, etc).

comdek · Dec 12, 2015

Now looking more closely, I have identified a fissure in cylinder head 5.
As the problem was identified now, I decided that I will not disassemble the other head, because the job is too big.

Alibro · Dec 12, 2015

comdek said:
Now looking more closely, I have identified a fissure in cylinder head 5.
As the problem was identified now, I decided that I will not disassemble the other head, because the job is too big.
View attachment 93732

That looks nasty. Can't you get a replacement head sent over from UK? Should be loads around as the engines were in lots of cars.

Nodge68 · Dec 12, 2015

As suggested, get a replacement sent over from here (UK). They aren't that heavy and you don't need the cams which will reduce shipping costs.
In theory it's possible to repair a crack like that in the head but replacement is a better proposition.

zefrench · Dec 14, 2015

Nodge68 said:
As suggested, get a replacement sent over from here (UK). They aren't that heavy and you don't need the cams which will reduce shipping costs.
In theory it's possible to repair a crack like that in the head but replacement is a better proposition.

How much does a single used v6 head could go for? Just curious.

Nodge68 · Dec 14, 2015

zefrench said:
How much does a single used v6 head could go for? Just curious.

Here in the UK, a stripped, second hand, perfectly serviceable head can be had from as little as 50 GBP.

comdek · Dec 14, 2015

Today the cylinder head returned from skimming. Good job. Waiting the gasket and reinstall all parts.

As the head was washed, I´ll will drop engine oil before closing the cover to the tappet and camshaft not working dry on start.

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