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Orange
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K series cooling

I have an 1800 k series with a recently fitted Radtec radiator. There is now slightly strange cooling issue.

If I start it let it warm up, it gets hot as normal up to about 80 deg on temp gauge, thermostat opens normally and water circulates to cool. Thermostat then opens and car cools. All pipes get hot. Then thermostat closes.

Then temperature climbs to just under 100 deg but no higher. However if I rev it, thermostat opens and cools to about 80 deg but then temp raises again to just under 100 deg.

The problem seems to be that the thermostat does not open unless I rev it but having said that it opens fine the first time on the heating cycle.

Any ideas?

 

 

 

Jonathan Kay
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Didn't happen with the old radiator?

Reasonably sure that there's no air in there?

What coolant?

I think that I'd swap the thermostat and see what happens. And have a good play with the existing one with a couple of pans containing hot and cold water.

Jonathan

Orange
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Thanks, thinking it is thermostat myself but trying to avoid taking it apart initially.

Coolant is Comma G30 premixed.

It did this before with the old radiator but was less pronounced. I.e temperature dropped slightly when accelerating but otherwise fairly steady mid 80s temperature.

I have been reading about the jiggle valve in the manifold and wondered if this could be the cause and I have some air in the system that I cannot bleed out (I have not seen any water return back to the expansion tank and this stays cold. Sound normal?

Martin

Jonathan Kay
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... and I have some air in the system that I cannot bleed out...

Which methods have you tried so far... jacking, massaging, extra bleeding T piece?

Jonathan

revilla
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It's not a triple pass race type radiator is it by any chance? I saw exactly these symptoms with one of those where the water pump just couldn't circulate enough water through the extra resistance of the radiator at idle.

SV VVC 170 - 170.4 bhp @ 7100 rpm - 142.4 ft.lb. @ 4900 rpm

Orange
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Yes all of that. I am sure I have all of the air out of pipes etc and the radiator. If I open the bleed tee or radiator bleed coolant comes out.

i am going to try jacking it higher and rebleed before taking it apart.

Is this just normal K Series nightmare bleeding do you think or dodgy thermostat. The thermostat was replaced last year just after I bought the car as I discovered that the previous owner had removed the thermostat completely meaning that the car took ages to warm up.

Martin

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Radiator is the standard Radtec, not triple pass as car will be mainly used on the road.

Jonathan Kay
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Andrew: Please check Private Message.

Thanks

Jonathan

7SW
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Hello,

 

I've added a bleeding T at the higher position of the circuit: no trouble to bleed the circuit since and without having to level up the front of the Cat

Orange
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Thanks, my car already has this. When I refilled the coolant, it came out of this tee first and then out of the radiator bleed screw. I thought I got all of the air out but now I am not so sure.....

Thanks anyway, any suggestions welcome and appreciated!
 

Martin

Fyldeflier
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I had very similar symptoms on my K series car.

Turned out to be the pressure relief cap. They are known to be unreliable.

worth a try.

John.