Sorry folks this is going to be a long one but I want to try and provide as much detail as possible to help you diagnose the problem

For those who aren't familiar with it the car is Grande Punto 1.6 Mjet sporting on a 59 plate that has had radiator problems in the past and had a new radiator put in not long ago due to a leak

If you've been reading the site cars project thread you'll know radweld was put in both Yellow and my car last weekend. My car did a run down to Dunfermline and back the day after it was put in the coolant system with no problems - 120-odd miles each way btw. It has since done 30-40 miles a day again with no problem although I have noticed it getting up to temp a lot quicker than before the radweld went in.

I thought I'd dodged the bullet but last night on a run into Aberdeen I noticed the the needle on the temperature gage going up. I put the heater on and it did go back down to where it normally sits however on the trip back home and again going to Alford this morning it was fluctuating.

Luckily Malfunction's brother Colin who is a very experienced mechanic was also at Alford and he looked under the bonnet for me. The first thing he discovered was the cap for the coolant reservoir hadn't been put back on properly and was introducing air into the system. There didn't seem to be anything else obvious wrong and we did hear the fan kick in at one point so we know that is working.

We needed the car to get back home so headed off. The temp needle still fluctuated but didn't do so in what I would consider to be normal over-heating conditions. It started going up either going round a corner or up a hill but would return to it's usual position on a straight or the flat. It even sat perfectly still slap bang where it usually is when we were stationary in traffic for 5-10 minutes having previously fluctuated

Martyn suggested an air packet in the system when it happened the first time after Alford so do you experts think he's right? And if he is right will it be damaging anything in the engine? What can I do to shift it or does it need to go to the garage?

Help please

Is the seal still in the cap? Could try another cap as well, these caps breathe to keep pressure constant to stop water boiling so if its got a broken seal then it might fluctuate.

Failing that, give the coolant a good flush using forte's, also where is the thermostat on these? If its in an easily accessible area, you could either change it or whip it out and check it, to check it just drop it in a cup of boiling water, if it opens then its working... so on and forth...

I think the seal is still there as Colin didn't mention it was missing and he had a good look. No idea where the thermostat is but hopefully abyss will be on at some point and I'd imagine he'd know.

Am I ok to run the car next week as it is or should I ground it until I can get it checked out?

It should be ok, just keep an eye on coolant level and temps.

Cheers for the advice.

My next decision is do I take it up to my usual garage, tell them the whole sorry story and put up with the eye rolls and/or laughter or try flushing it myself.

I think I know the answer to that question really [attachment=1:lj6v5jto]redface.gif[/attachment:lj6v5jto]

I think it'll be ok providing it's not actually overheating. Would just keep an eye on it for now and take action on it if it keeps happening.

Could well be an air lock or system pressure issue, i'm assuming you're getting hot air out the heaters though? i'd see how hot it gets, but it sounds like any air lock is small and the heater matrix is clear.

No it doesn't appear to actually be overheating. When we got to Alford this morning we checked the engine and it didn't appear overly hotter than usual considering it had been driven for nearly an hour and there certainly wasn't any steam etc.

As for the heaters, there wasn't much hot air in the morning but on the way home it was definitely nice and toasty with them on which was just as well as it had been bloody freezing at the autojumble. Ok, I'll keep an eye on it for now and see what happens.

Are you going to manage to head north on Saturday for the site cars Mark? If you can make it I'd appreciate you taking a quick look at my car just to reassure me

Why was Radweld added to the newly replaced radiator?...never been a fan of any of these additives, as they can block other small water galleries in the coolant system, or create transient blockages leading to inconsistent circulation...hence fluctuating gauge.

I'm with Stuart on this one...flush using a Forte product, then replenish with the correct ratio of anti-freeze/coolant.

It was added because I was still losing coolant. With hindsight I should have just taken it back to the garage but when the radweld was suggested it seemed like a cheap fix that could save me money. How wrong was I

The temperature hasn't fluctuated today however I've only done short trips of a couple of miles or so therefore it's too soon to tell. The worrying thing is the car is still getting to temperature far quicker than before the radweld went in so I expect to have an interesting drive to work tomorrow

Update time.

After a long weekend I went back to work on Tuesday. I got halfway there when the temperature gage needle started going up again however this time it wouldn't right itself. It may have been the exceptionally steep hill but I decided not to take the chance and phoned my garage and told them the whole sorry story. They couldn't promise much as they were fully booked all week but promised to do their best to find out what the problem was. After a few days of that deep-seated feeling of dread on my part and coping with the stupidly early rickety airport bus into work, the garage finally told me I need a new thermostat.

I know some of you will be expressing disbelief that radweld could cause that sort of problem so quickly however after a text conversation with Mark this evening it has emerged that it was probably a chain of events involving an underlying problem involving loss of coolant (hence the radweld), possibly the radweld itself, and the cap of the coolant reservoir not being replaced correctly. It's pretty much my fault as a) I should have taken it to the garage and not gone for a cheap fix on a car that is essential for commuting and b) checked under the bonnet as I knew the coolant cap had to be fitted correctly. My garage explained that to me when the coolant loss was first detected and told me it was ok to top up but to make sure the cap was on right

Anyway, looking on the bright side this may have actually helped me as hopefully the coolant problem has been sorted for good

Good stuff

Further update

Since the coolant system was flushed out the car has gone from heating up within a mile back to it's usual 5 miles in good weather. In winter I can be almost halfway to work before heat starts coming through the heater which I've always put down to extreme cold and it being a diesel but according to Derek, the guy who fixes my car, that shouldn't be the case.

the new thermostat arrives on Monday and fingers-crossed that solves all the problems in the mean time I'm still car-less and it's a real PITA

Hope the thermostat fixes the problem...Diesels are more thermally efficient. The heater in the Alfa takes an age to heat up, but you would think that the engineers would get round the problem.

Cheers gengis I hope so to. It'd be nice to have a car that warms up before I get to work this winter

Finally the car is back on my driveway

The garage is fairly confident all the problems are now fixed but time will tell if any long term damage has been done. The second leak was located to near the thermostat but don't ask me details as mechanical knowlege is not easily retained by my brain. I'm under instructions to keep an eye on the water level and take it back at the first sign of any loss. Derek is also confident the car will start heating up quicker than before now the thermostat has been replaced

I didn't have time to take it for a run tonight so tomorrow will be the real test to see if the air locks really have been cleared and if the new thermostat is more efficient than the old one

Derek's confidence was misplaced

The car got up to temperature quicker than usual this morning but no heat came through to the heaters until a good few miles later - roughly the same distance it would have done before the radweld went in/was flushed out. However even when warm air started getting into the cabin it did not feel as hot as it usually would but I still remained hopeful all would be ok as there was no sign of the needle moving.

I should have known better

Unfortunately on the way home tonight the needle did move slightly at the hilliest wyndiest part of my commute but it returned to it's usual position quickly at which point the car started warming up noticeably. So there's still air in there somewhere and if that is flushed out hopefully that will be it

Yeah that definitely sounds like an air lock, probably near the heater matrix. Would need to see if there's a second bleed point for the rear (some cars have them, some don't) and make sure both were done. Sounds like a smallish air lock tbh, if there was 2 bleed points then that should be a really easy one to shift

Cheers Mark I'll mention it to Derek when the car next goes in

My Spider's bad for air locks when refilling the coolant system, because of the low bonnet height, means that the radiator isn't the highest point in the coolant system. When I'm refilling the Spider, I help the air rising to the top of the radiator by jacking the front of the car up so the radiator is the highest point...may be worth trying this technique.

Sounds like there is a procedure to filling this system correctly, and additional bleed points should help this.

on a cinq there's a lower bleed point that comes off the radiator and an upper bleed point that comes off a heater matrix pipe, always liked that system of having 2, makes bleeding it absolutely fool proof... apart from when the plastic grommet fires out the lower bleed point meaning you have a choice of either loosing all your coolant or plugging the hole with boiling hot coolant pissing out with your finger until you look for it :laugh: