Tr4 overheating

[Bob Horner]

Hello again all. Just fitted alternator and thin belt conversion. As the rad was removed I flushed the system and refilled. The car now runs hot - halfway between normal and hot but it doesn't boil. Previously it ran just below midway. Checked and changed temp sensor and voltage regulator. Put on ramps to try and find airlock- doesn't seem to be one. Tonight restricted bypass hose- no difference. Have also swapped thermostat - new one reads exactly the same as old one.

 

Anyway, after running up to heat tonight I felt the radiator and the top few inches were too hot to touch but the bottom three quarters was barely warm. Does this indicate the radiator is knackered (or not quite up to scratch at least).

 

I know overheating as been done to death but couldn't find anything re assessing condition of a radiator so any help gratefully received.

 

Thanks in advance

 

Bob

Edited November 11, 2013 by Bob Horner

[MartinAndNeil]

If it doesn't boil it isn't overheating.

To clear any airlocks run the engine with the heater valve open and the rad cap off for at least ten minutes.

[Bob Horner]

Well I think if the ambient temperature was higher I think it would boil. Surely if it's running far hotter than normal something is wrong?

[Guest]

 

 

Anyway, after running up to heat tonight I felt the radiator and the top few inches were too hot to touch but the bottom three quarters was barely warm. Does this indicate the radiator is knackered (or not quite up to scratch at least).

A blocked radiator I would think or with air trapped inside.

 

You mentioned that you've flushed the system - perhaps there's loose scaling (is that the correct term in English?) blocking the waterways. Reflushing from bottom to top/opposite of the normal route can clear it.

But first, I recommend MartinAndNeils method as well. At least 10 min., heater valves open, front wheels high on a ramp.

 

Finally -and it's a wild guess- is the new narrow pulley properly attached to the pump?

 

Menno

[Bob Horner]

Thanks Menno. I think the pulley is fine. I was thinking that another flush may be necessary. I've already done the up on ramps running with cap off thing a few times and there has been no drop in level or indication of an airlock. I know a radiator is generally cooler at the bottom but I expected it to be reasonably hot not just tepid. Given that these problems occurred after a flush (using flushing solution) I did wonder whether I'd displaced some crud and it was blocking something. Should have left well alone.....!

[Badfrog]

Here comes chlorhydric acid 1N (diluted 1/36th).

Thorough rinse afterwards, please.

Don't do it on the Missus' garden pavement.

 

Badfrog

[peejay4A]

It might be worth checking that your thermostat is working properly and not jammed up with disturbed crud.

[BrianC]

If all the easy checks fail, do a full back-flush. Then make sure the entire system (including heater) is drained before refilling using a measuring jug to ensure that the correct amount goes in (i.e. if less than capacity stated in WSM, then you are probably getting an airlock - or it's going into the sump ).

Edited November 12, 2013 by BrianC

[Guest]

be careful when flushing the heater: the core of the heater matrix can not cope high pressure.

 

Menno