Exhaust gas in cooling water test exist?

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The car lost power and stalled at 65mph. Got to layby.

AA man did a test with a test tube type thing and said:

"You have exhaust gases in your cooling water, your head gasket has gone"

The car idled fine, would not pull away though. But after cooling for a while it went back to being normal. AA man said to tow me home though.

Does this test exist or was he having me on. Is it reliable? You'll see why I ask when you read on:

Now, I was so impressed with this quick diagnosis, that I lost all sense and within a few hours (quite a few actually) had the head off.

Gasket was fine ! Then I looked at the spark plugs (the sort of thing I'd have done ordinarily if I had not been daft enough or blinded by AA man)

2 plugs had cracked porcelain - gap was twice what it should have been on all plugs.

This could have been because I haven't serviced it when I should have or maybe an overheating problem, but it looks like I have wasted 2 days and nearly £200 in parts on the cylinder head.

If only I'd done my own diagnosis I'd have checked the usual and simplest things first.

Or does this test exist and is it reliable and did I have a small water leak that my naked eye cannot see?

The engine looks in really good condition for its miles. I do service it regularly and change oil well before time.

Ford escort 1.8 Zetec.
1998 year.
110k miles.

Any advice most welcome.
Cheers
 
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The test does exist, it is an indicator fluid which changes colour (from blue to yellow?) when it comes into contact with exhaust gasses.
The indicator is placed in a tube and the sniffer in the top of the expansion tank. The sample is drawn through the indicator by a bulb pump.
The indicator shouldn't change colour, as it did it is suggesting that exhaust gasses are present.
This could be a crack in the engine block, warped head or the head gasket has gone to name a few.
 
thanks Spark

Maybe I have been lucky then.

Block appears ok.
Head appears ok.
Gasket looks pretty darn good for over 100k miles.

The AA man said it could be just a small leak. Do you think this would have been enough to cause such a drastic loss of power?
I have lost hardly any water in the last 6 months. Others helping me think that even if a bit of water was getting in that such a drastic power loss would not have occurred.

Will see what a good head clean up (will check for any warp) etc and new gasket, head bolts, timing belt, aux belt, pulley tensioner kit, head kit and so forth does.

When rebuilt will do a compression test (can you believe I didn't do that first? Just started pulling it to bits so I did)

New HT leads and sparks and see how the old girl goes. Will keep an eye on the cooling water level like a hawk too.

Thanks for the answer.
Cheers
 
personally seeing as you have the head off mate, i would have it pressure tested.

also if you had a very very slight water leak into the block, it could cause the car to misfire, water interupting the spark.

also get yourself a complete new timing belt kit, with idler wheel,tensioner etc etc
 
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Thanks for that.

Was rebuilding today (until the blooming camshafts got mixed up and darkness fell).

Nearly £200 of spares; all the bits you've mentioned, new timing belt, aux, belt, idler pulley, head bolts (£55 third tightening stage is abit of a nervous time 105 degree turn after a 45Nm torque up already !), gasket of course, thermostat, cam cover gasket, etc - even got some K-seal just incase there is a small leak somewhere.

I'm just peeved in case I didn't have to do any of the above work and all I needed was new spark plugs. Absolutely ran like a dream (no misfires etc up until the total power fail (which went after a cool down)).

Going to be a week using wife's car now.

Learnt a lot though.
 
I don't want to depress you too much but there is a possibility that the mis-fire and loss of power could have been caused by sticking valves, the Zetec engine really does need a good clean 0-30 engine oil,have you changed the oil recently, or perhaps not changed it for a long time ? it is a very common problem with the Zetec units. :cry:
 
Thanks mobi.

Oil is changed very frequently (I get discount).

The engine looks in great shape (easy to see once it is lying all over the garage floor !) 120k miles and the cams and followers show hardly any wear.

Obviously there was some leak (as the test proved positive) but it may have been very small. I think failure was because I didn't change the plugs at last service (don't ask me why).

So now I've spent £200 on parts and changed the gasket (which looked fine). But the cam belt was due for its second renewal plus aux belt and idler pulleys I suppose.

Just got to put it all back together (parts are in garage, car is outside - ouch - bit cold right now)
 
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