Suspected blown head gasket.

[Robo]

Been chasing rough engine splutter .
All ign componits have been replaced, so not the problem.
Lpg converter been re-kitted .
Good compression.
Cooling system was well flushed and coolant was replaced 9 mths ago and level still good.
"But "
coolant has changed to a orange-ish colour from green.
And I seriously doubt it's rust.
Is LPG getting into the coolant and this is the cause of colour change.
Cant see water in oil or oil in water.

Looking at purchasing a block tester kit .
Car running still, keep it going for now, cant just pull head off.
Any thoughts on the gasket or head ??.
A typical gq head gasket let go may be?.

[Robo]

Tested the cooling system this-arvo.
No emissions in cooling system.

[threedogs]

Is your ride over heating // have you mixed coolants????

[Robo]

Is your ride over heating // have you mixed coolants????

No not over Heating.
Front timing cover developed a leak last year, r&r cover etc.
Did go from castrol anti freeze, to just the old castrol inhibitor, you got me thinking may be I didn't flush it, maybe I messed up and the odd colour is the result.
That doesn't explain the miss or low power surely.
I have read a few times here that the head gaskets have a tendency to let go, I assume with age.
If that's the case mine is only leaking between cyls and not into other systems.
1993 build, now 2013 so 20 yr old I assumegasket let go !.
Will test compression again tmoz.
I did sand blast plugs and replace em for a couple of days this week.
Noticed about 3 or 4 plugs had a little white spot on rear of earth when I removed em again.

Ok, Wednesday replaced all ign stuff under the bonnet again new.
splutter alot better as a result , splutter virtually gone.
Dosent feel like it's running on 4-5 cyls any more, "But" the miss is there in the background and power is still dropped away.
Possibly inlet manifold has a leak ( but can smell gas) , or the head gasket.
Remembering I started out LPG problem splutter after fuelling up, turned out to be more like a heat soak problem (I think).

Have new head bolt and VRS kit ready to go, just looking to totally rule out any other causes.
Have tried to jiggle the ign keys and barrel while driving, nothing funny happening while driving going on there.
The block test kit, Blue liquid, and tested yesterday and nothing there either.
Is it a known thing for em to let go between cylinders?
Getting sick of this @@##%%&&s

[Robo]

Dumb arse.
"why not do the old vac gauge testing , as found on the site here".
Result
Leaky valve seems to be the problem.
Compression results
1-------- 174 PSI.
2/3/4--- 171.
5------- -168.
6-------- 170.
Going by that I'll guess cyl 5's the problem.
The other (elec and lpg) problems, made it seem alot worse than just a valve.

VAC GAUGES SHOULD BE MANDATORY.
They really show up a problem.
And the lesson is, have a vac gauge on hand.
One gauge about to be mounted in Mav permanently.
And the head overall begins.

[happygu]

Dumb arse.
"why not do the old vac gauge testing , as found on the site here".
Result
Leaky valve seems to be the problem.
Compression results
1-------- 174 PSI.
2/3/4--- 171.
5------- -168.
6-------- 170.
Going by that I'll guess cyl 5's the problem.
The other (elec and lpg) problems, made it seem alot worse than just a valve.

VAC GAUGES SHOULD BE MANDATORY.
They really show up a problem.
And the lesson is, have a vac gauge on hand.
One gauge about to be mounted in Mav permanently.
And the head overall begins.

They are all pretty much within cooey of each other, and seem to be quite acceptable results. I don't see a problem here......

[Robo]

I agree that's why it had me a bit stumped, but the vac gauge said differently.
Mav drove a whole lot better on petrol than gas.

[Robo]

double checking myself.
Rechecked compression as gauge gave out on last reading on cyl 6, it was leaking after the check valve.
I fixed leaky hose yesterday and continued to read cyl 6, and didn't re-check 5 which was lower.
Today New Result all cylinders are as good as.
So no leaking valve according to comp test!!.
And I double checked this time.
Even with a dash of oil and comp jumped in every cyl.
So now it could only be a intermittent valve if it's leaking at all.
Gauge is still fluctuating a little.
I even disconnected the boosters today to make sure it wasn't a diaphragm leaking.%%##
Any ideas???.

[Robo]

Given the carb a clean whilst running and the fluctuating vac gauge has all but ceased to accure.
gauge only moves ever so slight not like it was , wth.
carbs off, cleaning, and re-kit.
see what happens then.

[happygu]

I did have a problem with my old MQ on gas, where the shaft for the float in the carby had worn and elongated the bushes on the end, from running on gas and just jiggling around with no fuel in the carby.

This was sucking in air, and upsetting the way it ran. Rebuilt carby and all good.....

[threedogs]

Looks like you may need stainless valve stems, and new seals and upper lubricant to replace the lead in fuel
Or get a gas head on a change over basis
Replace all vacuum and fuel lines, there's a thread somewhere saying the fuel line splits near the fuel tank on chassis
causing it to suck air, Meds kicking in all over the shop. I'll stick with split fuel line.

Have you removed all air from the system??
Park nose up and invert coke bottle in radiator, you'd be surprised
how much air you can remove

[Parksy]

Looks like you may need stainless valve stems, and new seals and upper lubricant to replace the lead in fuel
Or get a gas head on a change over basis
Replace all vacuum and fuel lines, there's a thread somewhere saying the fuel line splits near the fuel tank on chassis
causing it to suck air, Meds kicking in all over the shop. I'll stick with split fuel line.

Have you removed all air from the system??
Park nose up and invert coke bottle in radiator, you'd be surprised
how much air you can remove

It also pays to move the temp control in the cabin to hot then cold then repeat and watch for bubbles. I spent about 20 mins doing this. Frustrating, but it eventually got the air out.

[Robo]

Looks like you may need stainless valve stems,
Replace all vacuum and fuel lines, there's a thread somewhere saying the fuel line splits near the fuel tank on chassis
causing it to suck air, Meds kicking in all over the shop. I'll stick with split fuel line.

Have you removed all air from the system??
Park nose up and invert coke bottle in radiator, you'd be surprised
how much air you can remove

Ya mean Stainless valves ?.
Have Morreys bottle hooked up.
Not using any oil between changes.
Carby re built, the float pin holes were a little loose but ok I recon.
Running better, still not fixed but not far off now ( touch wood ).
Was defiantly worth the effort to kit carby out.
Think I'll take a look at plug gaps again.
Waved timing light over and spark is playing up wtf.
.7mm gap now for lpg, that gap was fine before.
Will try muckin around with ign AGAIN.
And bleed coolant as described above.
Also check fuel and vac lines.

Funny somewhere here, big leads were quoted as a waste of time as bosch make good leads.
A mate of mine reported back to me about his friend fixing an ign problem on a patrol with 10mm leads, as all else had failed.

Cheers

[Robo]

It also pays to move the temp control in the cabin to hot then cold then repeat and watch for bubbles. I spent about 20 mins doing this. Frustrating, but it eventually got the air out.

Can you please explain.
The interior heater system has no hot water tap.
The control only moves a door in the air duct system.
I don't understand why and how moving the heater control would do anything.

[Parksy]

No idea robo. All I know is the instructions for flushing the radiator specifically states to have the setting on hot and when I was bleeding the system moving the control from hot to cold made the level of water jump and bubble(using coke bottle trick). Can't explain it because I don't know anything about it. All I know is it worked for me. Can't tell me otherwise. Sorry.

[Robo]

No idea robo. All I know is the instructions for flushing the radiator specifically states to have the setting on hot and when I was bleeding the system moving the control from hot to cold made the level of water jump and bubble(using coke bottle trick). Can't explain it because I don't know anything about it. All I know is it worked for me. Can't tell me otherwise. Sorry.
All good.
Yeah manual states about the setting on hot whilst bleeding.
your guess is as good as mine.
I dont recall ever seeing a manual telling anything any differently about heater setting while bleeding.
maybe balances out the entire coolant capacity temperature evenly, something or other !.
Cheers