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3.9 v8 cracked head


SIMON64
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A cracked head on the RV8 is very unlikely, but the symptoms will depend upon where the crack is …………….. in fact, to generalize, the symptoms will be the same as cracked block / porous liner / slipped liner syndrome (a much more common problem)..............

Loss of coolant, pressurised hoses, and may be over heating.

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A cracked head on the RV8 is very unlikely, but the symptoms will depend upon where the crack is …………….. in fact, to generalize, the symptoms will be the same as cracked block / porous liner / slipped liner syndrome (a much more common problem)..............

Loss of coolant, pressurised hoses, and may be over heating.

hi do have loss of coolant my hoses do stiffen up but i would not say they were rock hard far from it it never over heats and runs fine other than my mpg has dropped to about 6mpg (dont know if mpg is related or a seperate problem ) i did put some K-seal in to try and stop leek but it still leeks had head presure tested they said it was fine so cant be head gaskit prob also had water pump replaced but cant find sorse of leek even tried using a dye in the coolant but still sign where water going

regards simon

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try a compression test first, that would show up a potential head gasket problem, if you can get hold of some uv leak detector fluid bung that in the coolant and see if there are any leaks.

does it use a lot of coolant?

hi sorry just edited my reply to say had done both of them and all was ok lol only loses coolant when running about 2 ltres a week

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Go for a longish run and get the engine hot (10 miles or so) ..................... then pull in and switch off for a few minutes (no more than 5 minutes) ........ when you restart the engine keep an eye on the exhaust and see if you get a large puff of grey smoke (burnt off coolant which is also leaning the mixture).

Also, on return from the run, remove the plugs whilst the engine is hot and see if any of them look cleaner then the rest (almost like its been steam cleaned) ?

It could also be a blown head gasket...................... a compression check will easily diagnose this ................... if the compressions seem OK on a cold engine then you will undoubtedly have a liner problem.

K seal works sometimes, but only in a very small % of cases.

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Go for a longish run and get the engine hot (10 miles or so) ..................... then pull in and switch off for a few minutes (no more than 5 minutes) ........ when you restart the engine keep an eye on the exhaust and see if you get a large puff of grey smoke (burnt off coolant which is also leaning the mixture).

Also, on return from the run, remove the plugs whilst the engine is hot and see if any of them look cleaner then the rest (almost like its been steam cleaned) ?

It could also be a blown head gasket...................... a compression check will easily diagnose this ................... if the compressions seem OK on a cold engine then you will undoubtedly have a liner problem.

K seal works sometimes, but only in a very small % of cases.

hi had compresion test done and that came back as good so cant be head gasket is a liner thing a big problem i know less that zero about cars so will need it to be fixed at a garage or some thing is this going to cost me mega money to sort out (what is a liner?)

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In general a garage would not see fixing a liner as economic .............. they will fit a replacement engine.

If the liner to block seal is porous then you either need top hat liners fitted (£800 - £1200 for the liners alone) or a replacement engine (£500 for a good runner or £1200 - £2000 for a short engine ................... on top of that you will have the garage labour to remove / refit and maybe build up the engine......for a completely fitted replacement full engine, then you wont get much change from £5000

To rebuild your engine yourself is going to cost about £1500.

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In general a garage would not see fixing a liner as economic .............. they will fit a replacement engine.

If the liner to block seal is porous then you either need top hat liners fitted (£800 - £1200 for the liners alone) or a replacement engine (£500 for a good runner or £1200 - £2000 for a short engine ................... on top of that you will have the garage labour to remove / refit and maybe build up the engine......for a completely fitted replacement full engine, then you wont get much change from £5000

To rebuild your engine yourself is going to cost about £1500.

so having had the head presure tested and is ok what is the likely hood that this is the problem and how can i tell find out for sertan that it is that, is there anything else that it could be or have i got a scappy on my hands

:(

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If the head gasket and liners are all fine then i would check all of the 'core plugs' especially any that might be fitted at the back (bulkhead) end of the block/heads for leakage. Also the inlet manifold might have a leak.

will do thanks for help

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I have just noticed yours is LPG ..................... check for coolant leaks around the vaporizer .............

Also have a good look around the underside of the water pump .........................

Often a small leak will evaporate before its obvious ................ you can sometimes tell from the discoloration that the coolant leaves when dry.

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I have just noticed yours is LPG ..................... check for coolant leaks around the vaporizer .............

Also have a good look around the underside of the water pump .........................

Often a small leak will evaporate before its obvious ................ you can sometimes tell from the discoloration that the coolant leaves when dry.

hi ok will check that the water pump is fine i have just had a new one fitted just in case it was that

cheers bud

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Hi Simon, your problem sounds a bit similar to the one i had a few months ago matey, I think you always assume the worst and think it'll cost you mega bucks. I was losing about 2-3 litres everytime i went out a run no matter how long or short the run was. It was a mixture of things. Expansion tank on it's way out,expansion CAP was shot and needed replacing, thermostat needed replacing as it wasn't opening up at the desired temp, timing was out by a good 10 degrees which caused it to run warmer then normal, and i think there was an airlock in the system too which was taken care of by undoing the rad plug at the top whilst the engine was running and poured water into it, carefull though as it spurted everywhere and nearly scalded my mate who was brave enough to keep pouring water in to make sure it kept filling up.After all that and after only spending about £15, Fitted everything myself and my mate done the timing with his light gun, it's....................well i'm not going to tempt fate but i haven't posted on here for a while :)

Hope it's somit simple;)

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Heads don't crack on V8s they warp, and gaskets won;t ehn keep it all in

Yours sounds either more like and internal leak (covered above) or external leak. you can get some leak visible dye to add to the coolant, this shows up far quick and clearer if external, worth a go 1st :)

Nige

hi have had this done with some kind of UV dye by local garrage they said they still could not find the leek thats why they did the preasure test on the heads but that came back good and are stumped as to what to do next

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Hi Simon, your problem sounds a bit similar to the one i had a few months ago matey, I think you always assume the worst and think it'll cost you mega bucks. I was losing about 2-3 litres everytime i went out a run no matter how long or short the run was. It was a mixture of things. Expansion tank on it's way out,expansion CAP was shot and needed replacing, thermostat needed replacing as it wasn't opening up at the desired temp, timing was out by a good 10 degrees which caused it to run warmer then normal, and i think there was an airlock in the system too which was taken care of by undoing the rad plug at the top whilst the engine was running and poured water into it, carefull though as it spurted everywhere and nearly scalded my mate who was brave enough to keep pouring water in to make sure it kept filling up.After all that and after only spending about £15, Fitted everything myself and my mate done the timing with his light gun, it's....................well i'm not going to tempt fate but i haven't posted on here for a while :)

Hope it's somit simple;)

hi dc i will take a look at expantion tank but if leek was from there would it have shown up with the uv dye how can i check if it has an air lock and would any of the things metioned on the topic be causeing the 6mpg thing or is that a seperate thing altogether

cheers dc regards simon

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Your 6mpg may very well be unrelated to this problem, I would try and sort your water loss out first then work on the fuel problem.I reckon if it was the expansion tank then some dye would be noticable, My cap wasn't venting properly either so this caused a build up in pressure probably causing the failure of the expansion tank. Airlock, how to know? Hmmm tricky one. All i can say on this one is what my mate done for mine. The rad plug on the top left hand side of the radiator (as your standing at the front of the car looking into the engine bay) was removed, then with the engine started, he kept topping up the level tight to the top, reved it up to and just kept topping up until it stopped spurting water out and sat at just below the very top, then plug went back on, took it for a run to build up some pressure and took the expansion cap off and let it rev, looked like it settled down alot and during every rev you could see the water was circulating ok.

When was the last time you had your timing checked?

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Your 6mpg may very well be unrelated to this problem, I would try and sort your water loss out first then work on the fuel problem.I reckon if it was the expansion tank then some dye would be noticable, My cap wasn't venting properly either so this caused a build up in pressure probably causing the failure of the expansion tank. Airlock, how to know? Hmmm tricky one. All i can say on this one is what my mate done for mine. The rad plug on the top left hand side of the radiator (as your standing at the front of the car looking into the engine bay) was removed, then with the engine started, he kept topping up the level tight to the top, reved it up to and just kept topping up until it stopped spurting water out and sat at just below the very top, then plug went back on, took it for a run to build up some pressure and took the expansion cap off and let it rev, looked like it settled down alot and during every rev you could see the water was circulating ok.

When was the last time you had your timing checked?

hi i have never had timing checked i have look at water level and have a go at what u surgest i cant take car 4 run at mo cuz it is out of tax and on a sorn regards simon

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