not convinced its the head gasket (1.8)

payner75t · 23rd October 2009, 10:47

had the car running on my drive for half an hour with no problems until i turned off the cliimate control, the cooling fan cut in and slowly the temperature went up. as i went to turn engine off i heard a knocking noise coming from behind the dashboard (?) which i couldn't hear from outside.
i turned the engine off and the knocking continued for a couple of minutes until the engine had cooled a little.
there is no sign of water in the oil or oil in the water.
any ideas.???

Parker · 23rd October 2009, 11:08

Whilst you have the aircon on the fan constantly runs.

If no aircon on the fan should kick in around the 99 degrees mark.

The knocking noise, was the aircon running then? Sometimes the baffle plates flap whilst they find their correct opening position just behind the dash.

Do you have a Hans Gauge fitted? If not a must for the 1.8's

payner75t · 23rd October 2009, 11:22

Quote:

Originally Posted by Parker

Whilst you have the aircon on the fan constantly runs.

If no aircon on the fan should kick in around the 99 degrees mark.

The knocking noise, was the aircon running then? Sometimes the baffle plates flap whilst they find their correct opening position just behind the dash.

Do you have a Hans Gauge fitted? If not a must for the 1.8's

the aircon was off when the knocking was heard ,also it stopped when i turned the aircon on!!!

Parker · 23rd October 2009, 11:30

Then I'm not sure, someone hopefully be along soon who may have an answer.

stocktake · 23rd October 2009, 11:41

I suppose another possibility could be a stuck t'stat. with the aircon on sufficient cooling to keep the water at correct temp. you do need to use the diagnostics to establish engine temp though.

T-Cut · 23rd October 2009, 18:31

Quote:

Originally Posted by payner75t

had the car running on my drive for half an hour with no problems until i turned off the cliimate control, the cooling fan cut in

Don't you mean cut out? Fan should stop when aircon is switched off. It will start again when engine temperature rises to overheat point. Gauge will remain normal at this point too.

Quote:

and slowly the temperature went up. as i went to turn engine off i heard a knocking noise coming from behind the dashboard (?) which i couldn't hear from outside.

How did you know the temp went up? Did the gauge go above normal?

Could you describe this knocking sound? Petrols have a fuel vapour recycler which taps loudly when engine is on tickover. Can be disconcerting when first heard. However, it stops when engine stops.

Quote:

turned the engine off and the knocking continued for a couple of minutes until the engine had cooled a little - - - any ideas.???

Baffling! Never heard a knocking sound with a stationary engine. Could it be heat expansion of the heater pipework?

TC

kaiser · 26th October 2009, 10:51

Noises most likely coming from the cooling system.
Sounds like severe air-lock. Most likely loosing water! Check.

23rd October 2009, 10:47	#1
payner75t Gets stuck in Saab 900 convertible,Ford Mondeo zetec tdci Join Date: Feb 2007 Location: Braintree Posts: 808 Thanks: 16 Thanked 7 Times in 7 Posts	not convinced its the head gasket (1.8) had the car running on my drive for half an hour with no problems until i turned off the cliimate control, the cooling fan cut in and slowly the temperature went up. as i went to turn engine off i heard a knocking noise coming from behind the dashboard (?) which i couldn't hear from outside. i turned the engine off and the knocking continued for a couple of minutes until the engine had cooled a little. there is no sign of water in the oil or oil in the water. any ideas.???

23rd October 2009, 11:08	#2
Parker This is my second home Jaguar XJ 3.0 V6 Auto (X350) & Hyundai Tuscon 2020 Join Date: Oct 2008 Location: Bridgend Posts: 10,342 Thanks: 69 Thanked 559 Times in 356 Posts	Whilst you have the aircon on the fan constantly runs. If no aircon on the fan should kick in around the 99 degrees mark. The knocking noise, was the aircon running then? Sometimes the baffle plates flap whilst they find their correct opening position just behind the dash. Do you have a Hans Gauge fitted? If not a must for the 1.8's __________________ http://www.the75andztclub.co.uk/foru...a585a72d1c.jpg "The only thing to do with good advice is pass it on. It is never any use to oneself" SOME VERY USEFUL LINKS SIMPLE DOOR MIRROR REPAIR FITTING CROFT DOOR FINISHERS FORUM RULES CLUB SHOP

23rd October 2009, 11:30	#4
Parker This is my second home Jaguar XJ 3.0 V6 Auto (X350) & Hyundai Tuscon 2020 Join Date: Oct 2008 Location: Bridgend Posts: 10,342 Thanks: 69 Thanked 559 Times in 356 Posts	Then I'm not sure, someone hopefully be along soon who may have an answer. __________________ http://www.the75andztclub.co.uk/foru...a585a72d1c.jpg "The only thing to do with good advice is pass it on. It is never any use to oneself" SOME VERY USEFUL LINKS SIMPLE DOOR MIRROR REPAIR FITTING CROFT DOOR FINISHERS FORUM RULES CLUB SHOP

23rd October 2009, 11:41	#5
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,591 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	I suppose another possibility could be a stuck t'stat. with the aircon on sufficient cooling to keep the water at correct temp. you do need to use the diagnostics to establish engine temp though. __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident

26th October 2009, 10:51	#7
kaiser This is my second home 75 Tourer 2.5 Auto, 1.8T, 75V8ZT Join Date: Jun 2007 Location: Johannesburg ZA Posts: 6,200 Thanks: 1 Thanked 859 Times in 613 Posts	Noises most likely coming from the cooling system. Sounds like severe air-lock. Most likely loosing water! Check.