Blown headgasket -Diagnosis

[john279]

What are the signs of a blown headgasket ??

-Mayo on oil cap
-Bubbles in expansion tank
-Loss of coolant
-Blown cooling hoses
-Loss of coolant in radiator, but high level of coolant in expansion tank
-Coolant blown out of expansion tank overflow

I'm pretty certain my headgasket is blown.

I've been soldiering on for months with various cooling problems at times, but it seemed to have stabilised, with radiator losing top 2 inches of water, but engine not overheating, so I could still drive car on long journey.

I think I blew the engine last Nov/Dec, car was occasionally misfiring, suspected condenser had gone, didn't change it as was too cold, but still made a few long journeys.
In Jan car overheated, top radiator hose had blown, changed the top radiator hose.

Car then oveheated again, changed radiator cap, didn't solve problem.

Tried using Kalimex K-Seal coolant system sealer, which helped a lot over last 3 months to stabilise coolant loss, but didn't stop it.

Changed points & condenser which got rid of the original misfire & loss of coolant reduced & became stable so I could drive car on long journeys without car overheating.

In between, the small radiator/engine coolant bypass hose blew, changed it.
Then recently the hose just under the carburettor blew, changed it.

All the time over last 4 months, at the end of a journey I would hear bubbles in the expansion tank bubbling away for 1-2 minutes.

But when the engine runs I don't notice any misfire.
Surely if the headgasket is blown the engine wouldn't run properly, would it ??

What do people think, is it a blown headgasket ??

Are there any other things I should check ??
.

 

[Ed]

get it to a garage who can test for exhaust gasses in the rad water. Thats a guaranteed test.

 

[Micra 110]

It'd be interesting to find out why all the Hoses blew.....A new Thermostat and a good forward and reverse Flush to the Cooling system would be a good start.

This is what happens if you don't change the Coolant very often :blush:

 

[whipit]

and really shouldn't cost more than a tenner.

 

[frank]

john

i usually fill the rad to the brim and look for bubbles on a fast idle, and sometimes the sparkplug gets steamcleaned on the cylinder thats ingesting the coolant (the one nearest the blown part of the gasket)
* waits for criticism *

 

[john279]

and really shouldn't cost more than a tenner.

What shouldn't cost more than £10
-the exhaust gas in rad water test ??
-new thermostat & reverse flush ??

It'd be interesting to find out why all the Hoses blew.....A new Thermostat and a good forward and reverse Flush to the Cooling system would be a good start.

This is what happens if you don't change the Coolant very often :blush:

Doesn't everything point to a blown headgasket & exhaust pressurising coolant ??

Could a faulty thermostat cause problems I'm having ??

Ps: Why does the board keep merging 2 posts, how do you stop it ??

 

[SammoHung]

What shouldn't cost more than £10

-> routine coolant change including new thermostat & reverse flush...but I ff you dont have any fresh antifreeze handy it will be more than a tenner...(more like 15 - 20 perhaps)

Thermostat - £6 ?
Tharmostat housing gasket - £2 ?
Antifreeze - £8 - £12?

Doesn't everything point to a blown headgasket & exhaust pressurising coolant ??

I think so

Could a faulty thermostat cause problems I'm having ??

Definately. when the engine gets to normal temp..the thermostat should open to allow water to circulate around the engine and radiator (to keep it from getting any hotter than normal operating temp)

if the thermostat is jammed closed (often through crust build up) then the engine will get hotter and hotter ...eventually alliminum cylinder head will warp resulting in fluids & gasses escaping past the gasket....sometimes the gasket can break as a result of this too

 

[whipit]

What shouldn't cost more than £10
-the exhaust gas in rad water test ??
-new thermostat & reverse flush ??

Both really, sorry about that micra 110 posted just before me.

 

[mickc22]

Hi everyone

thanks, that confirms that then.....
.....you could almost be talking about my K10, another job to the list :down:
I'll be replacing the thermostat too then

mick

 

[john279]

I think so

Definately. when the engine gets to normal temp..the thermostat should open to allow water to circulate around the engine and radiator (to keep it from getting any hotter than normal operating temp)

if the thermostat is jammed closed (often through crust build up) then the engine will get hotter and hotter ...eventually alliminum cylinder head will warp resulting in fluids & gasses escaping past the gasket....sometimes the gasket can break as a result of this too

During last 4 months I've regularly checked the radiator hoses get hot, showing thermostat is opening, so I didn't really think that could be the problem.

Since latest symptom, when the hose under the carburettor blew, the cooling system has become unstable, with coolant now rapidly pushed through radiator cap & expansion tank overflow. If I warm car up a little & stop I can see the water coming of expansion tank overflow pipe next to radiator.

In a 2 mile drive, lost top 2-3 inches of coolant in radiator & the expansion tank was virtually empty with engine rapidly starting to overheat.

I think the problems I've got are much bigger than what a faulty thermostat would cause.

What do people think ??

 

[john279]

I think so

Definately. when the engine gets to normal temp..the thermostat should open to allow water to circulate around the engine and radiator (to keep it from getting any hotter than normal operating temp)

if the thermostat is jammed closed (often through crust build up) then the engine will get hotter and hotter ...eventually alliminum cylinder head will warp resulting in fluids & gasses escaping past the gasket....sometimes the gasket can break as a result of this too

During last 4 months I've regularly checked the radiator hoses get hot, showing thermostat is opening, so I didn't really think that could be the problem.

Since latest symptom, when the hose under the carburettor blew, the cooling system has become unstable, with coolant now rapidly pushed through radiator cap & expansion tank overflow. If I warm car up a little & stop I can see the water coming of expansion tank overflow pipe next to radiator.

In a 2 mile drive, lost top 2-3 inches of coolant in radiator & the expansion tank was virtually empty with engine rapidly starting to overheat.

I think the problems I've got are much bigger than what a faulty thermostat would cause.

What do people think ??

 

[frank]

john

i think its just a catch tank on the k10, so you need an inch or two of air in the top of the rad (to allow for expansion)
did you try my suggestion of filling the rad to the brim and look for bubbles ?

 

[john279]

i usually fill the rad to the brim and look for bubbles on a fast idle, and sometimes the sparkplug gets steamcleaned on the cylinder thats ingesting the coolant (the one nearest the blown part of the gasket)
* waits for criticism *

john

i think its just a catch tank on the k10, so you need an inch or two of air in the top of the rad (to allow for expansion)
did you try my suggestion of filling the rad to the brim and look for bubbles ?

My K10 has an expansion tank off the radiator, where I get bubbles.

If I left radiator cap off, filled radiator 1-2 inches below top, radiator would just overflow. I'm sure I'd see bubbles there on normal idle.

I just did test, radiator full, expansion tank at correct half level.
Warmed car up, water rose to top in expansion tank, then pushed out of overflow for maybe 10 mins.

When I switched off car, get 5+ min of bubbles in expansion tank, then level in expansion tank gradually dropped to the bottom of expansion tank.
So had lost 4+ inches of water in expansion tank & probably top 2 inches in radiator.

Couple of months ago I checked cylinders, took out spark plugs one by one, engine continued to idle on 3 cylinders when spark plug removed for each cylinder.
Could not see any water in any of the cylinders.

 

[frank]

john

i stand corrected :glance: , all the k10,s i,ve seen had a tall, thin white catch tank on the side of the rad.
it sounds like the head gasket to me, but without seeing it, its hard to be sure

 

[Holty]

Mines a MA12 engine and i have no catch tank, just the rad with a cap on it

Its got hot lots to the point it has missfired and cut out
The rad was full of thick brown sludge, i suspect an oil gallery is seeping into the coolant. seems better now with clean rad and fan on constant lol
I just hope the head aint warped :down:

 

[gruff]

John

I would check the oil mate as if the oil has water in it then ur gasket has gone, we do it all the time at nissan, if not then give us a shout and i'll get back to you