Heater problems Elan plus2

[rogerh]

I have studied many articles on the subject, but can't seem to find one that addresses my particular prob.
After about half an hour when running at a steady speed (say 3500-4000 revs) my heater goes cold and remains that way until I stop and let the car idle for a while. I have tried the following :-
1) flushed the system out with radflush
2) back flushed the heater matrix
3) jacked the car up at the front and filled the rad with the engine running to clear any air locks.
Nothing I do seems to help (have a 80c thermostat fitted) and the engine runs at about 85c most of the time and the kenlow fan rarely cuts in even when stuck in traffic.
HELP!! WINTER'S COMING AND IT IS A CONVERTIBLE
Roger h

[alexblack13]

Hiya Roger,

If it were not for the fact that your engine 'runs around 85 deg' ' I would say your 'stat had stuck open. You also say that the fan 'rarely' cuts in even in traffic'. I have to say with standard radiator etc this is very unusual. Is the rad' st'd? or have you fitted a big one? It looks like you are overcooling. Apart that is for the temp guage. Could it be over reading a bit? The heater element is well capable of pulling a lot of heat out of the water.

Heater hoses in good nick?? No deterioration to the inside of the hoses?

Keep in touch and let us know what it is...

Bbrrrrrrr....

AB........

[types26/36]

How about the heater radiator (matrix) being partially blocked, try disconnecting the inlet and outlet heater hoses and blowing compressed air through it.

[alaric]

Hi. Sounds like a blockage, but if you find that it's not the matrix as suggested, the rubber hose that crosses over from the thermostat housing has a 90 degree bend in it just before it goes through the bulkhead. It may be, that when it gets hot, the rubber goes soft and it collapses, shutting down the flow of water. You can reach the hose with the carbs in place so it may be worth having a feel before you strip anything out. Just a suggestion so sorry if it's wrong.

All the best.

Sean.

[ebc699]

Hi Roger,
Sean's theory I think could be worth investigating since the bend he mentions has quite a tight radius. When I had the engine out of my Plus 2, I replaced that section with a moulded piece of hose which helps.
Hope this helps.
Cheers,
Wylie

[rogerh]

Hi Guys,
Thanks for all the replies, here is the latest update :-

Last eve I ran the engine from cold whilst in the garage at 12-1400 revs
After 10min. the temp read 80c and the heater warm-
Further 10mins saw temp of 90c and Kenlowe fan cut in-
Reduced revs to 800
Five minutes later Kenlowe off and heater still blowing hot=
Thereafter temp varied between 80c and 90c with the heater hot and the Kenlowe cutting in and out!
I took the car out today and did a 70mile trip out and 70mile trip back with 2hr rest---55minutes each way----temp. stayed steady at 80-85c all the way (dual carriage) seems the thermostat is working ok.
Murphy's law rules ok!! The heater functioned PERFECTLY!!
(A friend who followed in an identical car got to 110c on his temp gauge.)
The only thing I did before the trip was to disconnect and blow through the heater return pipe (next to thermostat housing)---there was no resistance through the heater matrix and the air bubbled up through the radiator.
It may be I shifted something in the pipe. I suppose the fact that I gave up smoking some time ago helped.
Anyway thanks again for help I'll let you know if the problem returns. Rogerh

[john.p.clegg]

Roger

You did 70 miles in 55 minutes on a dual carriageway?? If I was you I'd check your milometer accuracy and repost before the plod issue you with a ticket.....

John

[alaric]

Glad your elan feels better after a good blow.

Glad it's sorted now.

Sean.