Bars Leaks for Radiators: Advice please

[paul c]

I noticed last night that the coolant level in my car, a Saab 9000, had dropped. In years gone by I used to put a bottle of Bars Leaks (like Radweld) in the coolant reservoir to sort out any problem like that. However, from time to time you hear rumours of people who've ended up with blocked waterways (I know this was a problem with some 80's and 90's Rovers.) Does anyone have any suggestions or thoughts? It may be the heater matrix as this is a common (and labour intensive) failure on these cars. If I were to use this stuff would it be best to flush the coolant out a couple of weeks later to remove any excess and so avoid any build up of deposits?

[alfasud]

I guess the first question is - where is the water going? If you run the engine, are there any visible leaks? You may have to crawl under the car to check? Could there be a blown head gasket, which would imply water getting into the oil - is the oil clean or foamy?

[paul c]

I will check the oil but I suspect it's not that. I've test driven a car (I didn't buy it!!!) with a blown head gasket before and it was showing problems with temperature control whatever the driving. What alerted me to the problem was the temperature coming up a little in traffic. As soon as I got moving again it came straight back to normal.

[Maisie]

Hmm... that's exactly what mine's doing at the moment, Paul. You've got me worried now

[ghinzani]

tell me about 1200 quid for a new head on my beemer...

[Dick Spanner]

You say that the coolant level dropped but you didn't say when you last checked it. It could be a really small leak from a loose hose. As Alfasud say's you need to find out where it's going and how quickly before you take any further action.

[paul c]

Also just noticed that even though it's topped back up now the temperature is warming up when it's stood on tickover. It's the first time I've noticed the electric fan need to cut in, but as I say, when it's moving there's no worries.

[Spudgun]

If it's okay when you're moving, then the head gasket should be fine.

We once had a problem with the head gasket once on the long journey. To get home we had to cruise no faster than 50 mph and switch off the engine at traffic lights due to rocketing temps.

I would run the engine and then look eveywhere for water coming out in every nook and cranny you can find.

A friend of mine recently was loosing colant, but couldn't find a leak. He eventually narrowed it down to an air lock in the coolant system that was triggering an excess release valve. It was only activated when driving because of the extra pressures involved. The car was a diesel Peugeot 405, but I'm not familiar with Saabs.

[paul c]

Thank you all for your comments so far. I have a sneaking suspicion that it may be the heater matrix since there is a slight smell of burnt antifreeze, almost like burnt sugar, when the heater is switched on. Does this sound likely?

[Neil C]

You might be on to something there PC.

Maisie, your problem might also be the water pump, or thermostat/temp sensor...much cheaper than replacing a head gasket and whatever other damage might be caused by water in the crankcase. If your oil is looking milky and foamy, then you have a gasket problem. Let's hope not.

[Maisie]

Tried swapping the thermostat - no difference. Temp sensor was changed a couple of years back, but they're known not to be too reliable. I did have a crack at the water pump, but some muppet's killed the allen key bolt that holds it in. It seemed to be turning freely enough. The oil seems OK, apart from escaping more rapidly than I'd like from the engine!

I'm hoping to get another car on the road in the next few months, which means I can take this one off for a total nut and bolt rebuild.

[Crash Test]

We had an overheating problem in the Mondeo a while back, did some fiddling around to find that the hose out of the radiator was knackered, changed that and still not much chop. It was ok if you were running down the highway, but would go up when stopped, and had really bad heat sink. Then we found that the bottom fan motor was burnt out... no problem, get another one in it! Rock up to work... ermmm, that's an $800 part (!!!). Luckily a dope in the workshop dropped a fan assembly a week early, but the motor part we wanted was still good- and what was best, they gave it to us!

I must admit to being a tad anally retentive when it comes to watching gauges and levels and things, and since that was fixed, it's proving hard to get the temp off cold... it was never that good, it must have been on the way out for a fair while

[Valve Bounce]

There are many hose connections in modern cars which could leak, not to mention that hoses still preish. The smell of burnt anti-freeze could simply be the leaking water dripping onto the hot engine. The trouble with modern cars is that hte engine bay is chocker block full of stuff and you can't see much of the engine's hoses and their connections. I think that checking all the hoses for rubber perishing might also be in order. A hose can look perfectly normal until you bend it - then the cracks show up. Any signs of perished hoses means that hose must be replaced before it suddenly leaks really badly.
I don't think bars leaks will solve leaking hoses. If you can reach all the hoses, I'd wait till the engine was totally cool, then take all the hoses off and check them.

[graham bahr]

maybe its not what you want to hear, but have you thought about letting a reputable garage pressure test your cooling system? its something i often do at work, it doesn't cost much as the rad cap is simply removed and the cooling system is pressurised to normal operating pressure with air, we then go away and leave the car for an hour or so, water leaks in the engine bay usually show up as a puddle on the floor which is easy to trace back to its origin on a cold engine.

if no leaks show up the engine is either using the water internally (ie head gasket/crack etc) that being the case we check the cooling system for the presence of hydro-carbons ie un burn petrol which are always present when head gaskets start leaking,

or and the anti freeze smell you have already noticed suggests you have a leaky heater matrix.

i stopped using bars stop leak years ago, but for a vey long while i have been using a rad stop leak made by a company called "Forte" its only available to the motor trade
but i have cured literally hundreds of leaks with the stuff and never suffered a blockage, i even had one customer who had a cracked head on his 325 bmw who had me put some in as a tempary meassure, we did have to eventually replace the head but that was 2 years and 30,000 miles later