Help - SLR K series overheating

[sak]

K series recently overheating and blowing coolant from expansion vessel. Car quickly cools and quickly reheats. Limped home with heater on full blast! ☹️

Am I correct in thinking it needs a new thermostat? Some research suggests they don't all have a thermostat?? , and if it is located where I think it is it looks like a pig to get off.

Any advise/suggestions (apart from learning something about engines!)?

Cheers

[Stationary M25 Traveller]

Easier to remove the bolt that holds the diptube and thermostat housing and remove the housing. Then undo three bolts and swap thermostat. Drill 3mm hole in what will be the uppermost part of the flange when fitted ... check this ... it only goes in one way up. Note which side spring face is as you remove the old one.

 

Consider doing the cooling system mod while drained. See Sept 2012 LF. Cheap and easy mod.

[rj]

Hmm

 

HGF?

 

Be careful not to wreck your cylinderhead.

[John Hughes]

Try a new pressure cap before doing anything more drastic

[Nick Woods]

You might want to have a read of my thread here.

 

In summary, mine kept blowing coolant and/or leaving a high coolant level in the header which went down when i opened the bleed valve on top of the radiator. After a great deal of hassle and several visits to various garages, including three tests for exhaust gases in the coolant which found nothing, it did turn out to be the beginnings of head gasket failure.

 

I'm not saying that's what you have but you may want to have a read through and compare your situation to mine There have been a few cases similar to mine since then, it appears that there is a mode of gasket failure which causes a gradual increase in pressure within the system.

[Eugene]

I agree with John H...

Check pressure cap (radiator expansion bottle cap) first.

They fail with exactly that effect.

[Allen Payne]

Also check that the fan is running when the engine it hot

[myothercarsa2cv]

Had this quite early on in ownership, cap swap, fixed. Do that first, as suggested. If it still does it, then there's a problem!

[Englishmaninwales]

Cap failure, air lock, HGF and cylinder head porosity can all cause these symptoms. The latter can be cured see here

 

Malcolm

[sak]

Thank you all for you advice, much appreciated.

Will try new pressure cap first, presumably this one here

 

By the way, fan is not running when hot and excuse my ignorance but what is HGF?

Cheers

[mav]

Head gasket failure.

 

If your fan is not kicking in, first thing to check is it actually works. If you have a switch in the top of the rad remove the two plugs and short them together to see if fan runs.

 

If it does check you have a full rad of coolant.

 

Does the bottom hose get hot at all? This will give a clue on the thermostat.

 

 

[Sim]

Head Gasket Failure ☹️ ☹️ ☹️