Head Gasket Failure - How to tell; by Russell

10 years 11 months ago - 10 years 3 weeks ago #6430 by russell
Thousands of words have written about why the K series engine suffers from head gasket failure, not everyone agrees with the reasons offered and with so many differing opinions owners and prospective buyers are left confused & worried to the point of paranoia.

Many things can shorten the life of your head gasket, from a simple inexpensive expansion cap failure to thermal shock and everything in between.

The fact is the original designed head gasket is very vulnerable, where other gaskets would be able to cope with minor leaks or an air lock the K series original gasket cannot; it is also true the original gaskets do deteriorate over time, even without the cooling system having any problems.

The best advice I can give is to keep regular checks on the oil and water levels as both will tell you all you need to know and give you an early warning, better still invest in a low coolant alarm.

Some common symptoms that your head gasket has failed

Thick creamy looking oil and an unexplained increase in level and/or Oil contamination in the expansion tank and less common is an external leak from between head and block.

If you have any of the above there is no question, your head gasket has failed.

Some common reasons why you could be losing coolant

  • Failed expansion cap - A failed expansion cap will show as coolant staining on and around the expansion bottle.
  • Leaking water pump - A leaking water pump will show as a leak dripping from the crankshaft pulley behind the driver’s rear wheel.
  • Leaking under floor pipes - Leaking under floor pipes will show as leak between the front and rear wheels left hand side.
  • Leaking radiator - A leaking radiator if only slight will need a careful check as it could just be staining, if a larger leak coolant will be found on the floor front centre under bumper.
  • Leaking inlet manifold gasket - A leaking inlet manifold gasket can show as (a) a cold start misfire (b) coolant staining down the block, gearbox side (c) coolant dripping on the floor or a mixture of the three.
  • Split hose - A split hose will be a leak to ground.

This is not a full and complete list but the more common areas that can and do fail, and with limited technical skills most will be able to diagnose and fix the problem.

Do not continue to use the car until the leak has been found and repaired.


I could go on and on but thought it best to keep it simple trying to avoid adding to the confusion surrounding the K series head gasket phenomenon.

Remember just because your loosing coolant does not automatically mean your head gasket has failed but if you ignore the signs it most definitely will.
The following user(s) said Thank You: Leigh Ping, Gudleif, Sanchez, Uncletone, mgtfbluestreak, bob46, sworkscooper

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2 years 4 months ago #186864 by jaybe64
I just took thermostat out ripped guts out refitted and put the later PRT in like the lotus has been doing for years . the thermostat opens to late with original as engine gets hot so quickly so it can't cope with it . you can buy second hand ones for the mgft which run this system for around £50 with all the hoses and the thermostat .

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