Hellfire
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| posted on 26/7/13 at 05:19 PM |
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Possible Head Gasket Failure?
Having had a couple of overheating issues this last week, we drained the coolant last night to replace a suspected faulty fan switch in the radiator.
The water was a dirty brown colour and smelled of exhaust/oil fumes, although no oil is visible in the water and no water is visible in the oil.....
Coolant had been lost somewhere though and I suspected a head gasket failure. We refilled the system and took it for a short run. The engine seemed to
stutter a bit in first gear and didn't rev cleanly, as though there were air bubbles in the fuel but was fine in the higher gears with no signs
of overheating. After turning the engine off, the fan cut out but the header/expansion tank was bubbling? We noticed the car was also difficult to
restart and keeps cutting out.
Do these sound like the symptoms of a head gasket failure allowing exhaust gases into the coolant and a small amount of water into a cylinder?
Having never experienced a HGF before, any advice would be welcome.
Phil
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matt_gsxr
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| posted on 26/7/13 at 05:37 PM |
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I am no bike expert (although I have suffered a few HGF), but it does sounds like HGF is likely.
Have you had a look at the plugs, if one of them looks nice and clean then its been steam cleaned, which is a dead giveaway.
If you look at the zx12r block it is easy to understand why you might well not get oil in the water. The oil-ways have little to do with the cylinder
seal area.
A new head gasket is only a 4hour job though and its going to rain on Saturday.
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Jon Ison
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| posted on 26/7/13 at 05:38 PM |
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One sure sign is the hoses "pumping up" have you squeezed then whist the engine is running if there rock hard then that points to head
gasket for sure, worth a quick check.
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Hellfire
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| posted on 26/7/13 at 06:01 PM |
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Not checked the hoses Jon but will definitely give it a go. Last time it overheated, the oil temperature reached 140 degrees  Could it be anything
other than a head gasket failure?
If water is getting into one of the cylinders, wouldn't white smoke/steam be visible from the exhaust?
Phil
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benchmark51
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| posted on 26/7/13 at 06:03 PM |
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If you know a friendly garage they might poke their exhaust probe into your header
tank and sniff out combustion gases.
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Mikef
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| posted on 27/7/13 at 07:31 AM |
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Can you scrounge a compression tester from some one? Fairly sure way of checking.
Mikef
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adithorp
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| posted on 27/7/13 at 08:06 AM |
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I'd say you've got a head gasket failure  Sorry.
I'd guess the gasket has just started to leak compression gasses into the water jacket. At first it'll only leak in that direction as the
compression is enough to push the gass through but the failure not big enough to let significant amounts of coolant into the cylinder (so no steam
from the exhaust) so you get compresion smell, excessive presure and overheating. So far the failure hasn't got between oil and water so no mayo
or cross contamination.
If you continue to run it it'll go down hill fast. It gasses could eat into the head/liner and make a proper mess! The fact it's getting
harder to restart indicates wateris going the other way (when standing) already. Check the plugs (and look down the bore) for one being steam cleaned.
Try starting from cold, run a couple of min's and switch off before it heats up; Has it built presure in the coolant tank?
No oil/water cross contamination just means it's not leaking between oil feed/water jacket/oil gallery. Remember head gaskets seal a lot of
things (cylinders, water jacket, oil feed, oil return galleries/crankcase and the outside world. They can leak between any two and in either
direction. Thats a lot of combinations and the syptoms will be different... and thats before you get leaks between several.
[Edited on 27/7/13 by adithorp]
"A witty saying proves nothing" Voltaire
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