Technical Engine heats up & Runs On

[Aldino]

Good morning guys!!!

yes, i'm back with a problem. this time around i understand my car a bit better and better at spotting a problem. :bang:

i've been running the car at the current settings for two weeks now - for about 1000km.

1.)lately she's been running a bit warmer than usual - especially while i'm driving, it will tend to go over 90dgrs. the fan kicks in fine.
2.) when i switch off she runs on for a while.

the change in heat i don't get - running on i geuss it's the idle speed set too high... if so, why is it only acting up now? - i had it at this idling speed for the last two weeks.

i would also have difficulty starting her up when she is warm. it would take about a minute or 5 to start again.

thanks guys


OOOOPS!! Hi Alex....

just read one of your posts where you advised against putting "Bars-leaks (sludgy black pellets)" into coolant... well that's what i've put in. i was a bit sceptical about the product.

my car: 2000 1.1 Uno (Mia).

 

[jjhepburn]

Wow a 2000 model uno cool

Maybe the black stuff is contributing to the overheating. The running on could be caused by bad petrol?

 

[Trancendental]

Bars leaks, is that similar to Rad-Weld which stops radiator leaks temporarily? That may be making your car warmer as it may swim around with the water for a while.

You over running might be to do with bad fuel (As stated) or a rich fuel mixture. Reducing the Idle speed would help.

 

[alexGS]

I wouldn't be hugely worried about either symptom, if I understand correctly. What happens if you take it for a 'hard' drive, up hills etc. Does the temperature go any higher then? Up to 100 degrees is acceptable, but really there should be no change between 'normal' and 'hard' driving, as the cooling system should have plenty of reserve capability.

If the temperature does rise when driven hard, you could try back-flushing the radiator (disconnect both hoses, maybe remove the radiator from the car, put a hose turned on full into the bottom hose fitting, hope that any blockages flush out OK...) Then flush out the system and replenish with coolant only. I think it will then sort itself out.

Transcedental, yes I believe Bars-Leaks is similar to Rad-Weld. Before buying, it's worth a quick shake of the bottle to listen for chunks - worth avoiding. I prefer a thick green liquid product sold by Wynns in a purple bottle as 'Radiator Stop Leak', as I've never had any problems with it. It has solved a few difficult leaks such as one at the turbocharger on my Uno Turbo - a small threaded pipe that was already done up tight... which must be under pretty extreme conditions! It hasn't leaked for years now, even after flushing/changing the coolant - a true success for stop-leak!

In the USA, Alfa Romeo dealers were advised to 'dose' the 164's V6 engine with a stop-leak solution when necessary, since there were often leaks from the myriad of hose connections to the various aluminium castings despite the clips being tight. http://www.digest.net/alfa/FAQ/164/b079301.htm I've thought that if it was OK for them to use on new cars, it's OK for me.

I also want to make it clear that I use stop-leak AFTER I've already replaced/refitted the obvious items, I wouldn't expect it to fix a leaky water pump, for example, or a loose hose connection. But it might extend the life of a suspect head gasket; has to be worth a go if lots of work is involved otherwise!

I agree with you Aldino that the running-on (also called 'dieseling' since the engine is effectively running like a diesel does!) is probably caused by the idle speed being too high, but it will also be made worse by the engine being hotter than usual, and possibly also by the fuel being low-octane (ignites too easily) as jjhepburn said. What is your idle speed, anyway? It can usually be brought down to something under 1000RPM. I guess you're having to go by ear with the 1100

-Alex

 

[Aldino]

Great stuff

Answer: up hill she tends to get a bit warmer. i also realised our season is changing here in South Africa, so it is getting pretty warm even early morning. gave her a good clean out. Used Wynns radiator flush aswell. topped up with anti freeze and Wynns Stop leak. went to bed at 02:00am and up at 05:00am... so now i need a cosy corner. she is running like her old self again.

the heat does not go over 100dgrs. the fan kicks in fine. she starts immediately even when the temperature is 90-95dgrs. i also realised i've put Wynns into my sister's Uno a year ago, sealed up the small leak and is still running hassle free.

Aaaah, the elusive rev counter. maybe i should pop in a rev counter. problem is i don't know what the rev should sound like. i think i saw a thread about installing a rev counter... is it adviseable or worthwhile?

thanks again Guys :worship: great advice.

 

[alexGS]

Good that you've got it sorted out!

I personally think an instrument cluster swap with a more upmarket Uno is the best solution for the rev counter, but another way is to look for an ignition tester (dwell meter, now redundant with electronic ignition) or even an automotive multimeter as these usually have a tachometer function that you can use for adjusting the idle speed (FIAT tachometers/rev counters tend to over-read anyway at idle speed).

Or, you can just adjust the speed (with the engine fully warmed up) until the engine runs as slow as possible while still being smooth. This will get you somewhere close to the target of 850RPM. Ideally you should be able to rest tools (socket spanner etc.) on the top of the air filter housing without them falling off

Having the engine idling slower will have other benefits, like being able to engage reverse gear more easily...

-Alex