head gasket

[slideways]

Hi All
i think my head gasket may be blown,is it that difficult a job to do? and can anyone give me an idea as to cost if i need the heads skimming ,i take it both will need to be skimmed and a list of things to do to replace them.
my symptoms are i,m loosing a lot of water somewhere but cant find a leak anywhere, the cooling system gets highly pressurised no mayo and no clouds out the exhaust,
any help greatly appreciated
Thanks in advance
Rich

[mb450]

Sorry to hear of your woes. I recently had my range rover 4.6 heads skimmed cost was 75quid+vat.

Off of the top of my head for your chim you'll need

Valley gasket and valley seals
Head gaskets
Arp head bolts
Manifold gaskets
Oil
Antifreeze
Rocker cover gasket

Might be with checking the state of your cam whilst you're there.

I'm sure someone with more recent experience will be along on a sec with a more comprehensive list

[GreenV8S]

See if you can get a positive diagnosis before you get the spanners out. You should be able to detect HC contamination in the coolant with a block tester, or oil contamination in the water, or an obvious leak from a cylinder leakdown test.

[spend]

Its enough of a job & cost to make really sure you don't have a leak first. You can pressurize the system via the filler, might be SH that sells a kit? Alternatively stick an airline on one of the throttle heater pipes

[slideways]

Thanks
so does the oil need changeing as ive recently done it?
do you need extra sealant on any of the gaskets?
Ta
Rich
greenv8s and spend sorry i missed your posts, i was going to do a leak down test and block test tomorrow if i can get the kits in time,
spend can you tell me more about connecting to the throttle heater pipes and what it will tell me
Ta

Edited by slideways on Wednesday 19th November 20:50

[Chimjunkie]

slideways said:

Thanks
so does the oil need changeing as ive recently done it?
do you need extra sealant on any of the gaskets?
Ta
Rich

Certainly no sealant on head gasket! None necessary on cylinder head cover rubber seal either. The passenger side head is easier than the drivers side. Better access i found. Less to take off.

If head gasket is gone then you would expect one or more of the following?

• Smokey exhaust
• Water in oil (drain sump to examine. If ok put oil back in)
• Bubbling through expansion bottle. (take cap off, start cold engine and look for constant bubbling as thermostat opens - Also worth doing HC hest as mentioned above)
• Low compression on one or more cylinders - (Compression test on warm engine)

How much water are you losing? You could have a leak in the heater matrix which may then make carpets wet. Easily mistaken for rain leaking in.

[slideways]

Chimjunkie said:

slideways said:

Thanks
so does the oil need changeing as ive recently done it?
do you need extra sealant on any of the gaskets?
Ta
Rich

Certainly no sealant on head gasket! None necessary on cylinder head cover rubber seal either. The passenger side head is easier than the drivers side. Better access i found. Less to take off.

If head gasket is gone then you would expect one or more of the following?

• Smokey exhaust
• Water in oil (drain sump to examine. If ok put oil back in)
• Bubbling through expansion bottle. (take cap off, start cold engine and look for constant bubbling as thermostat opens - Also worth doing HC hest as mentioned above)
• Low compression on one or more cylinders - (Compression test on warm engine)

How much water are you losing? You could have a leak in the heater matrix which may then make carpets wet. Easily mistaken for rain leaking in.

from your list the only thing ive seen was bubbles in expansion tank
im putting about 1 ltr in every 50miles maybe less

[Chimjunkie]

One other thing, if you are going to remove the heads make sure you document where every part is from. I.e shims under which rocker pedestals, push rods must go back as they came out. Really you should reset the valve preload, but you may get away without doing this if everything goes back exactly. UNLESS of course you have the heads skimmed. Or the new gaskets are thicker/thinner...oh bugger, best redo the valve preload!

[Chimjunkie]

slideways said:

from your list the only thing ive seen was bubbles in expansion tank
im putting about 1 ltr in every 50miles maybe less

That may not necessarily be from the heads. Could be air trapped in system. If you are losing that amount of water i think you would have running problems and more symptoms on the list. I'm no expert but I would suggest it is a water leak. Best try what Spend said above.

[spend]

There are 2 small bore pipes that go from the manifold & heater pipe to underneath the throttle housing, these are commonly bunged up on TVR's (just the pipes). You can just connect them to a compressor and gradually shut the reg to bring the pressure up. Best done whilst the car is warm (not hot), just get the top hose so you can feel decent pressure and look see if any of the hoses are weeping. Dribbles underneath the nose of the water pump are another common area.

[slideways]

Thanks guys
that should keep me busy for a bit

[Barkychoc]

I don't want to be the bearer of bad news but could this be a cracked liner?

[Chimjunkie]

Barkychoc said:

I don't want to be the bearer of bad news but could this be a cracked liner?

If it were, where would the water be going? If into the oil he would have seen this when draining the sump. If into the combustion then the car would smoke? Interesting.