I suspect the head gasket is beginning to go on my son's car as it needs half a litre of coolant every hundred or so miles. It's done 120,000 and there is no sign of a leak anywhere else. The dipstick is still pure oil but there is a bit of hard mayonnaise on the oil filler cap.
My question is, is it worth trying something like Holts radweld at this stage...or just wait for the inevitable progression?
Also, is it worth cracking then retorquing the head bolts to make a better squeeze of the head onto the block and perhaps squash the possible microscopic connection between water system and cylinder?
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whatever u do dont crack th headbolts all u will do then is make it worse..these head gaskets do rot with age and start to leak..its best to sort it now properly rather than wait and break down....1st thing to do first is get someone to check that there is exhaust gas in the water this will tell u the head gasket has gone..if u need a gasket doing get the head bolts replaced as its not worth reuseing the old ones.buy the best gasket u can as there are some real cheap and nasty ones out there..the mayo on the filler cap is not much to worry about as they all seem to do it on this engine..
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Thanks for the advice, jayeastanglia. Exhaust gas in the water? Is this some test for CO2 in the coolant or did you mean water/steam in the exhaust gas?
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Exhaust gas in the water? Is this some test for CO2 in the coolant ....
It's a test to see if hydro carbons are present.
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Thanks, DD. I've never heard of this test - is it a new thing? Would my local friendly motorspares shop have a testing kit?
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No, it's not a new test. No idea if your local motorspares will have a kit. It's usually done with a gas analyser. You could try asking your local chemist whether something like litmus paper would detect hydrocarbons.
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I'm puzzled, although at least it's clear the test is done on the exhaust gas.
Litmus detects changes in acidity. Chemists correct me if wrong but I thought hydrocarbons [basically diesel, petrol or LPG as far as cars ar concerned] were neutral. Surely if there was a microscopic defect the only extra stuff in the exhaust gas would be steam. I suppose if there was a substantial leak some unburnt hydrocarbon might get through but isn't the cat supposed to pick that up?
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No, if the gasket is going, combustion products will escape into the cooling circuit, so you can test for them in the radiator or overflow tank. I think 'litmus paper' was a figure of speech, DD?
Edited by Andrew-T on 17/02/2009 at 17:52
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Andrew, not being a chemist, and not studied Science for over 25 yrs, it was a total guess, re: the litmus paper.
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Puzzlement continues. So far we have a gas analyser from DD and some sort of test for combustion products in the coolant from AndrewT. Clarification, please! Which particular gas/product is being looked for?
I am beginning to think a litmus test might actually be correct - if you bubble carbon dioxide [clearly a combustion product] through water you get carbonic acid which would turn litmus paper red.
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The confusion is because they are 2 different tests.
The gas analyser (as used in the emissions test at mot time) will detect unburnt hydrocarbons, and wrong co if the engine is not running correctly.
The coolant test is basically a "sniffer" test of the coolant to check for the presence of combustion products and/or oil in the coolant.
really dont know about the litmus paper test.
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