Over heating

[Stevearniepalmer]

I have a standard 1967 Saloon with an after market temperature gauge fitted.
Recently I took part in a parade where I was travelling in first gear stop start for about 3 miles.This sent the temperature gauge up to 95oC .To try and bring the temperature down slightly we opened all the windows and pushed the heater on button .Was this the correct thing to do? A few days later we got stuck in traffic and the same thing happened again.
Also every time I stopped the ignition light came on and the engine cut out.

I was able to restart each time but wondered if anyone has any suggestions for me about what to do.I tried to leave a gap between cars and then started off again to make sure we were moving for the most amount of time possible.
Also would it have helped if I had pulled out the choke very slightly .I didn’t try it because I didn’t want to not be able to start again.

[simmitc]

I wonder what thermostat you have fitted? 82 degrees is normal for summer, 88 for winter. If it's got an 88 at the moment, then in the hot weather and slow traffic, 95 might be expected. Is the gauge accurate? Not all are. Is it wired correctly - does it need a stabilised supply?

Turning the heater on and opening the windows was a good move and does provide extra cooling for the engine, if not for the humans.

Check your fan belt tension is correct and the belt on good condition.

Ignition light on tickover can happen if the idle speed is very low, and that could also cause stalling. It might be worth increasing the idle speed slightly - use the throttle stop screw on the carb, do not adjust the mixture (unless it needs it, but that's another topic).

[Stevearniepalmer]

Thanks for the advice.
I think I have an 82 thermostat because it usually sits around that mark .The gauge is new and from a reliable source so I’m fairly confident it’s working properly.As I’m not mechanically minded I’ve just had her MOTed and serviced so hopefully they might have picked up on the tension of the belt etc.
With regard to the throttle stop screw can you explain where exactly it is please.As I said I’m not mechanically minded but would like to try and sort it out before the weekend when I drive to the National.Also does your comment about the mixture mean that I was correct in not pulling out the choke slightly.
Thanks again
Steve

[svenedin]

Turning on the heater was a sensible move. I have done that too and we managed to limp home.

The first thing I would do is take the radiator cap off and check the coolant level. Also the condition of the coolant. If the level is too low there may be a leak somewhere. If the water is very rusty there could be too much sludge in the cooling system which leads to poor flow. It is safest to check the coolant with a cold engine as taking the radiator cap off a hot engine could scald you. If you must do that, turn the engine off and let it cool down for 15 minutes and then use a thick cloth to slowly undo the radiator cap.

The suggestion to check the fan belt tension is a good one because that pulley also operates the water pump. Often a loose belt will screech under acceleration.

Sometimes a thermostat can fail shut or it no longer opens enough. With the engine up to temperature, check the hose coming from the thermostat housing. It should be hot but if cold or tepid that is the problem. Changing a thermostat is in theory a simple and quick job but the thermostat housing is made of aluminium alloy whereas the block is iron and the studs are steel. Corrosion can turn this job into a bit of a trial.

To adjust the idle speed, look up SU HS2 carburettor idle setting screw. You say your car is 1967 and standard so I assume that means you have a dynamo? Set the idle so that at idle the red charging light is just going off or flickers (this assumes the charging components are in good condition). You asked about using the choke to control the idle as a temporary on the road fix. That is OK. The first bit of travel of the choke only affects the idle; it has to be pulled out further to adjust the mixture.

Let us know what you find and we can go from there.

Stephen

[myoldjalopy]

On the subject of sludge causing overheating, many years ago a traveller I then had overheated on a long run, blowing out via the rad cap. The first I knew about it was brown liquid oozing through the bonnet flash! I stopped and climbed down to a nearby stream for water and topped up the rad. I drove on with no further issues and it never overheated again from then on. It must have blown enough of the sludge out itself to solve the problem!

[svenedin]

On the subject of sludge causing overheating, many years ago a traveller I then had overheated on a long run, blowing out via the rad cap. The first I knew about it was brown liquid oozing through the bonnet flash! I stopped and climbed down to a nearby stream for water and topped up the rad. I drove on with no further issues and it never overheated again from then on. It must have blown enough of the sludge out itself to solve the problem!

Yes. I had a heater valve explode recently. Whether that was overheating related or a poor quality valve I do not know but it alerted me to the filthy state of the coolant. I gave the system a very thorough flush with a garden hose and I never thought the rusty water would clear. It did eventually. I then did 2x cycles of Holt's Speedflush and unblocked the engine block drain as well. Finished by filling back up with distilled water (from my condensing tumble drier) and Bluecol antifreeze. No problems since.

Stephen

[simmitc]

If you have not managed to get it sorted by next weekend but do manage to get to the National, then there will be plenty of people about who will be able to guide you further.

Note that an MOT will not check the Fan belt, but a service should.

[Stevearniepalmer]

Thank you for all the info .I should have said that the car came with an alternator so therefore not entirely standard.Sometimes I forget because these things are just there.I also have full electronic ignition as well.
The radiator is newish and hasn’t lost any liquid at all.I don’t seem to need to fill it very often.I do about 2500 miles a year.
I will try the idling speed and see what happens.
Thanks
Again
Steve

[Stevearniepalmer]

Hi Guys
Another update.
I drove 167 miles to the National Rally on Friday and Audrey didn’t miss a beat.We even got stuck in some traffic and her temperature gauge although it went up which is what I would expect it to do it didn’t affect her performance.The pipe that was mentioned does get hot so that means everything is working as it should.
Thank you for your advice everyone I shall keep an eye on the idling speed and adjust if I feel I need to.
Thanks
Again
Steve

[oliver90owner]

The gauge is new and from a reliable source so I’m fairly confident it’s working properly.

My advice is to check, not guess. Assumptions are often wrong. This seems like it may well have not been overheating at all?

Checking the readings for a temperature gauge is easy. Checking the operation of a thermostat is easy - unless changing it anyway, as they can stick in one position intermittently.

On another (very recent) thread the poster failed to check the oil pressure gauge - which was reading completely erroneously - but there were several (frankly wasted) posts on changing/altering parts on the engine. I see it all the time - posters recommending changing parts instead of testing them. Perhaps they like spending other peoples money or can’t be bothered (or don’t know how) to systematically diagnose an apparent fault.

[philthehill]

Nothing is wasted on here.
There are other people reading the posts who will gain valuable knowledge.
Subsequent posters can only reply to what the O/P askes or states.
The subsequent posters are not mind readers and give an opinions or advice at a distance and detached from the problem.
If the O/P cannot give the right question or description in the first instance that should not reflect on subsequent posters.
Phil

[svenedin]

Whilst I agree it is entirely possible that the temperature gauge was indicating a false temperature, what the OP described did sound like overheating. Temperature rising too high in crawling traffic is a typical symptom of a sub-optimal cooling system. I also thought the engine cutting out when stopping was heat related (fuel vaporisation). Perhaps it was a sludge problem and by chance the blockage has cleared. I would expect the problem to recur without diagnosing and rectifying the issue(s).

[myoldjalopy]

Engine cutting out when stopping at lights, junctions etc. can also be a sign that a service is due, particularly to the spark plugs and dizzy if this was not previously a problem. Whenever my car has shown a tendency to cut out when stopping, a clean and re-gap of the plugs and points has always cured it.