Cleaning radiator fins

rmunns · Post by **rmunns** » 30 May 2009, 00:10

[[1998 Xantia 1.8i 16V]]

I have had a little bit of a fright after reading a recent post regarding the possibility of overheating problems if the water system is not bled properly after refilling.

Last week I finally got round to looking at the dead-end regions round the radiator where gunge could accumulate. I removed the radiator and found about a third of the region between the aircon radiator and the water radiator was full of leaves, dirt, etc etc. I could also clearly see that the fins on both rads were dirty.

So, hot detergent solution sprayed between fins then rinsed out with high pressure jetwasher.

Really pleased with the job; only bad bit was getting the radiator out. What a task, if only the designers had left another few mm clearance.

But when I consulted Haynes for replacing and refilling the fluid, I could see that there was some doubt as to just where the bleed nipples are for each model. I did fill using a high reservoir and this was successful, but I could only find ONE bleed nipple (on bulkhead, going into or coming out of heater). This bled ok.

I've done about 250km since then, radiator header tank still same level of fluid . But yesterday, after starting from cold I saw the gauge was slower than normal in rising up from the start point. Having had several cars overheat in my time I do keep a close eye on the temp gauge and this just didn't seem normal for the car. But the gauge still reads midway between 60 and 75 when up to temperature, except when idling for more than a couple of minutes.

Main thing I am asking is :::::::::::: how many bleed nipples should I have found? Sorry to be so long before getting to the point.

addo · Post by **addo** » 30 May 2009, 01:53

I think there's also a brass-headed one on the thermostat housing.

DickieG · Post by **DickieG** » 30 May 2009, 07:20

You raise a good point about the radiator fins on Xantia's as the weather is now warming up for the summer. When I had my Activa (now Jim's), on hot summer days with the air conditioning running the temperature gauge would continue to rise until either I lost my bottle and turned the A/C off or the fans went onto high speed. Looking at the radiator/intercooler/A/C condenser from the front through the cooling fans they appeared to be clear of obstructions but when I unclipped the radiator and pulled it back I discovered all manner of debris had managed to get through the intercooler and condenser but collect on the radiator. I used a long thin nozzle on a vacuum cleaner to clear it all out which worked a treat and sorted the problem out.

VertVega · Post by **VertVega** » 30 May 2009, 09:25

There are two bleed nipples and I have added pictures in this thread:
"Coolant flush ... " http://www.frenchcarforum.co.uk/forum/v ... hp?t=26913

You have found the leaf collector

I clean it once a year. It is very simple.
Just release 2 clips on top of the radiator and slightly bend it towards the engine. It doesn't have to be removed completely.
Air pressure or garden hose can be used for cleaning.

Another important issue about the temperature rise (over 100 C) in slow traffic can be because of the radiator fan motors. I have replaced both of them last year.
There are lots of items in the forum. Cloggz has sent a great amount of information and pictures on that.

rmunns · Post by **rmunns** » 30 May 2009, 19:52

Thanks so much for the picture.

This confirmed the thermostat bleed screw. My car is a 1.8 16V and the bleed screw is identical to this picture. I had dismissed it as a bleed 'cos it's a capscrew, allen key head.

Just that one journey, three or four days ago, had shown unusual warm-up on the temperature gauge, after 3 years of identical behaviour every journey. I'm paranoid about losing an engine through not carefully watching the gauge. Saved a Subaru XT on the motorway when a top hose burst, amazingly luckily 3 markers short of services!

Have now bled this one and the heater bleed as well, engine running, radiator cap on.

BTW I have often run cars with the cap loosely on (not pressure tight) if I've had a leak in the system. Less water loss, no danger IMHO if the engine is not caned / weather not hot. Can get-u-home if water loss is a problem.

Deanxm · Post by **Deanxm** » 30 May 2009, 20:12

Hi gents

Yes it is always worth getting in and cleaning the leaves out from between the rads

Killed the intercooler on this XM and the rad behind it too

D