Cooling dramas - HELP!!!

Dave · tinkerer Joined: 04 Oct 2001 Posts: 322

OK kids,

Here's the problem.

My BreadVan is heating up frequently. Usually at about a steady 60kph, the temp rises to above half, then stays there. If I'm accelerating - say I'm rowing through the gears in traffic or in the Hills, then it's OK.

But as soon as I hit a constant speed - 60, 80, 100 - you name it, it warms up a bit too much for my liking. It doesn't boil, but it could if the weather was hot enough.

I've had 3 Geminis and the previous two stuck to the one temperature like glue. They would only waver if it was about 40 degrees in heavy traffic or if they did have a problem.

This is what has been checked:

Radiator - OK
Thermostat - OK
Hoses - OK
Heater core - OK

There are no blockages in either heater nor radiator. The thermostat is nearly new and is the correct one for the car. The cap is OK - and is nearly new.

I'm out of ideas - it's not as though Geminis have an overly complicated cooling system. Quite frankly, I'm stumped, as are the guys at Natrad who are trying to fix it for me.

Fresh perspective please - can anybody shed any light on this????

Dave

Fastgem · tinkerer Joined: 04 Oct 2001 Posts: 166

Id say check your timing and mixtures, had a similar prob a while back on a long drive and retarding the timing a few deg didnt fully fix the prob but it sure as hell helped (yeah i usually carry a timing light around with me), It is also possible to get a new thermostat that is stuffed.
Are you loosing any water?

Benjamin · backyard mechanic Joined: 05 Oct 2001 Posts: 525

It is possible that retarted timing could cause overheating, just thinking about what fastgem said.

What are your plugs burning like?
The only other thing I can think of is that it is running too lean down low, but you would have that sorted Smile

The other question is how well she has been running lately, whether you have noticed a gradual/slight power drop over time. One would hope your engine isn't getting a tad tired.

Dave · tinkerer Joined: 04 Oct 2001 Posts: 322

Thanks for your suggestions - both you and Benjamin.

I don't reckon it's timing though, because if it was, I'd notice that the Breader would be running like a dog, which it isn't.

It generally runs like a dream and revs really cleanly all the way to 6000rpm. I only do stuff like that when the engine's been running for at least 10 minutes. Anything under 10 minutes and I never take it over 3000rpm - and that's only when I'm driving. If I'm not running late, I warm it up a bit first, so then it's never under 2000rpm.

I gave the car back to the radiator boys this afternoon. They have been driving it around trying to replicate the problem and couldn't get it a peep over standard operating temperature until they turned on the headlights...

Hmmmm. At first, I thought they were talking rubbish and bullcrap, because on the weekend I did some serious urban driving, helping my chicky move house. But then I remembered that the weather was absolutely shithouse and it was raining the whole time (her brother was helping and wrote his Magna off into the back of an identical Magna - hooray!!!)... and I had my headlights on for safety reasons.....

Hmmmm, I shall be interested to get to the bottom of this. I just wish it hadn't cost me $183 to work out that the cooling system is NOT the problem.

We shall see...

And if anybody else has any suggestions of what it could be, don't hold back.

Cheers,

Dave

Mooch · backyard mechanic Joined: 17 Oct 2001 Posts: 573

Dave, i have experienced similar strange happenings with my gem. remember how i told u that it was running @ 100deg? well, a temp gauge works on resistance right? when i have the stereo cranked it pulls the gauge to 100-110, turn it off, back down to 80. strange but that's what seems to be happening. i'd check all connections, senders etc etc. i'd even go as far as replacing the wire from the sender and seperate it from the loom. For 60 bucks u can pick up a good vdo gauge as well. I am going to have to pick myself up a better alternator.

Good luck bud
adam

LOK15 · Posted: Wed Jan 09, 2002 11:33 pm Post subject: Re: Cooling dramas - HELP!!!

If you flick the headlights on and off while watching the temp does it jump up n down.
IF so you have a bad earth connection.I have had a similar problem that has developed from nowhere.
Check all the under bonnet earth connections they may look ok, but they could be trying to earth out through the lights earth or something else
GOOD LUCK!!!
_________________

Adam · Site Admin Joined: 04 Oct 2001 Posts: 682

Dave · tinkerer Joined: 04 Oct 2001 Posts: 322

This is gay!!!

I've tried to replicate the problem. But when I turned the headlights on, the temp needle didn't fly straight up - it just gradually wound it's way up. Then when I turned the lights off. Sure as eggs, it just gradually drifted down again.

However, I'm not fully convinced that's the whole problem. The car also warmed up over the standard temperature without the lights on, but only AFTER they had been turned on and off again. It was about 35 degrees this morning and the needle didn't budge from it's resting place just below the first notch on the gauge. I didn't turn the lights on at all.

Fortunately, my mechanic doesn't mind fiddling with electrics and getting to the bottom of a serious problem. Unfortunately, he's on holidays for another couple of weeks.

Cheers for your help anyway. Keep the ideas flowing if anybody gets inspiration. I'll let you know what the outcome is when it's fixed up.

Cheers,

Dave