94 1.7 17DTL Cracked Cylinder Head. - Railroad.
First thing every morning my car starts with a misfire for a few seconds, and a puff of white smoke/water vapour comes from the exhaust, after which it would run perfectly fine. Also over a period of several months I've noticed a small loss of coolant. I pressure tested it and cannot find any evidence of an external leak anywhere. I began to wonder if these two problems were related. If I released the pressure when I finished with the car at night it would start and run normally the next morning with no misfire, and that led me to suspect that the head may have a small crack which is closed when it's warm, and opens up when it cools, allowing coolant to run into one cylinder overnight, hence the slight misfire in the morning. It has never shown any signs of overheating, nor has it got worse in over two years which leaves me convinced that it's not the head gasket which has lifted.

I bought some 'Irontite Ceramic Motor Seal' from a local engine machinist. It was just over £20 but I thought was worth the gamble. It is a professional engine sealant that coats the entire cooling system with a ceramic coating. I read the instructions on the bottle and decided to use it. Last Sunday I drained the cooling system and re-filled with water. I did the same on Monday and Tuesday to ensure I'd got rid of the anti-freeze completely. I ran the engine right up the fan cutting in on Wednesday evening and added the sealant. I'll drain it out tonight and let it stand overnight to cure, and I'll put it back together tomorrow morning. The sealant contains ceramic beads which by capillary action are drawn into any minor cracks and porous areas. It then hardens when the system is drained and comes into contact with oxygen, providing a permanent seal. Once it's gone off the system can be re-filled with anti-freeze.

Since I've added the sealant the engine has not misfired at all when starting, and both my wife and myself are convinced that the car performs better overall. I'm therefore very optimistic that the problem will be cured.

If anyone else has a similar problem then this looks like it's the product to buy.......

94 1.7 17DTL Cracked Cylinder Head. - Railroad.
After two days there has been no misfire or smoke when starting in the morning. Without speaking too soon I'd say it's now cured.......
94 1.7 17DTL Cracked Cylinder Head. - Peter.N.
Don't know anything about this sealant but your initial problem could well be head gasket leakage.
94 1.7 17DTL Cracked Cylinder Head. - Railroad.
Don't know anything about this sealant but your initial problem could well be head gasket

Possibly, but on a diesel engine with a compression ratio of about 18:1 I'd say it's unlikely. Once head gaskets have lifted on any diesel they tend to go quite quickly, and usually due to engine overheating. My car has never overheated in the nine years that I've owned it......
94 1.7 17DTL Cracked Cylinder Head. - roosterbooster
hi railroad these engines have a known tendency of cracking inlet valve ports. just remove glowplugs and see which one is rusty!
94 1.7 17DTL Cracked Cylinder Head. - panther

I have the same problem on my 97 GM low blow 1.7 td. I do know that the head that was fitted did have a very slight crack forming across one of the ports. Starts first turn of the key from cold but a slight splutter for a few secs but after that it runs well but it is a tad down on power. It does lose a fraction of water but is very inconsistent. Sometimes the level doesn’t move from one week to the other & other times a top up is needed after a week. There does seem to be too much pressure in the cooling system – even if it’s been left all day, if the level looks low and I come to remove the cap you can feel a lot of pressure releasing and forces the water back up to the max mark again.

94 1.7 17DTL Cracked Cylinder Head. - Railroad.

Hi Panther.

I posted this thread three years ago, and I no longer own the car. However I would like to say that after I'd added the Irontite Motor Seal I never had the problem again. With this in mind it might be worth giving yours a go with it. £20 is obviously much cheaper than a new cylinder head. Just one word of advice. Read the instructions carefully and make sure you follow them to the letter. If you do it'll work fine.

Edited by Railroad. on 01/06/2011 at 21:23

94 1.7 17DTL Cracked Cylinder Head. - panther

Thanks railroad, I'm keeping an eye out on ebay for a cheap head (local breakers seem to want more money that the old vans worth but if I can't drop on one cheap will give that motor seal a try. I said I'd scrap it once it reached 200k miles but its almost reached that now and still plods on well & good mpg so might spend a few quid on the ol gal to keep her moving along.


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