Overheating issue - Airlock?

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Tiger Tim
Posts: 220
Joined: Tue May 22, 2007 11:18 am
Location: Ireland

Overheating issue - Airlock?

Post by Tiger Tim »

Hi All,

I've my MK1A for 10 years now & have changed the coolant a number of years ago with no issues. Yesterday I was driving to a show. Weather was very hot. After about 50 miles the temp gauge shot up into the red having been sitting in the middle for all the journey up to that. I quickly pulled over & switched off. Was driving at about 50mph at the time. Radiator did not feel very hot & coolant in the bottle was just above max. No fans running. I restarted the engine & slid heater to hot. Immediately the temp returned to normal. I drove on the last 10 miles to the show with the heater on & no issue. I tested turning off the heater & immediately the temp started to rise.
For the journey home I put the rad fans & the engine bay fan running continuously & gauge sat just below the centre point. Engine temp didn't rise & weather was seriously hot & hot inside car with heater on. About 5 miles from home I turned off the heater & the temp gauge didn't budge.
I've searched for this issue on the forum & it looks like it could be an airlock or possibly the thermostat,

Anyone got any suggestions. Had trouble with a faulty gauge a few years ago but when this reacted when I put on the heater, it's probably OK.

Tim
Tiger Tim
Posts: 220
Joined: Tue May 22, 2007 11:18 am
Location: Ireland

Re: Overheating issue - Airlock?

Post by Tiger Tim »

Update - I removed to filler cap this morn & there was a large "burp" from it. Coolant looks low looking in thru' filler. Must get some coolant.

Anyone got any suggestions. Bleed the system?.

T.
jimi
Posts: 2139
Joined: Tue Dec 14, 2004 10:27 am
Location: Kingdom of Fife
Contact:

Re: Overheating issue - Airlock?

Post by jimi »

Sounds like an airlock to me, I'd go with bleeding the system. Might be worth considering this method http://myweb.tiscali.co.uk/jimilawson/V ... oling.html its always worked for me :wink:
markstevieandmads
Posts: 2025
Joined: Mon Aug 05, 2013 8:18 pm
Location: Swindon, Wilts

Re: Overheating issue - Airlock?

Post by markstevieandmads »

Thermostat stuck closed?
Tiger Tim
Posts: 220
Joined: Tue May 22, 2007 11:18 am
Location: Ireland

Re: Overheating issue - Airlock?

Post by Tiger Tim »

Thanks for the replies.

I bled the system over the weekend. Was a good bit of air in it. Think it's all out now. No gurgling to be heard.

Went for a spin last evening and temp gauge sat just below normal. Heat never rose. Hopefully solved.

Thanks for the help,

T.
SonicSW20
Posts: 3681
Joined: Mon Nov 29, 2010 7:54 pm

Re: Overheating issue - Airlock?

Post by SonicSW20 »

Great you sorted it.

Monitor it closely - you may have a very slow leak somewhere.
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