Overheating

Neil · Post by **Neil** » Mon Apr 30, 2007 1:29 pm

Dear BX fans,

I have a Dec 88 16 RE. Recently, it has been experiencing something of an overheating problem in that when it is idling or not going very fast in London traffic, the stop light has been coming on. The water level in the radiator seems to be going down, although not particularly quickly.

Over the weekend, Dad and I replaced the thermostat. However, that doesn't seem to have rectified the problem and the fan is coming on awfully late. We wonder if there could be a blockage in the radiator and that could need flushing.

Any suggestions would be much appreciated.

Best wishes from Neil

stuart_hedges · Post by **stuart_hedges** » Mon Apr 30, 2007 2:06 pm

Whenever I've had cooling problems, it's been a silted-up radiator. It's quite easy to check - just run the engine until it's warm, then (carefully) pat your bare hand all over the radiator. If you find any cold spots, there's a blockage.

In theory you can clean them out with something like caustic soda, but personally I wouldn't bother - if the rad's silted up, most likely it'll be rusty and want replacing soon anyway so you might as well just replace it now.

I once had a Rover P6 rad re-cored at a local place in Kent for about £80, and the other time I needed to replace one (on a CX) I got it second-hand but known to be good for (I think) about £30. Can't remember where from, now.

It's not a job I've done on a BX before but it was pretty easy on the P6 and the CX.

Best of luck, and whatever the problem turns out to be, sort it soon before you find yourself stuck in an embarrassing cloud of steam and puddle of water!

Neil · Post by **Neil** » Mon Apr 30, 2007 2:14 pm

Thanks, Stuart! There are dead parts on the radiator.

I think the easiest way is to get another radiator.

Best wishes from Neil

jeremy · Post by **jeremy** » Mon Apr 30, 2007 3:17 pm

Yes - you'll need the new rad - the problem is that these are crossflow radiators - like most modern ones. Old ones flowed from top to bottom and any sludge would collect harmlessly in the tanks at the bottom. The bottom tank is now vertical on the off side of the car - so the sludge collects in the tubes themselves. All is ok - you can loose a few - until the thing is put under stress when it'll overheat!

You may be able to clear it by flushing but bear in mind that the blocked tube is very small and about 2 ft long - so what are your chances of shifting it?

Oscar · Post by **Oscar** » Mon Apr 30, 2007 4:32 pm

If you're doing the rad, do the fan switch and pipes at the same time.

Welcome to the club, btw.

Mr B · Post by **Mr B** » Mon Apr 30, 2007 5:02 pm

Neil wrote:Thanks, Stuart! There are dead parts on the radiator.

I think the easiest way is to get another radiator.

Best wishes from Neil

Keep your eye on EBay as new rads for petrols seem to turn up for handy money. Or stick a post in For Sale bit on here, someone might have a good'n knocking around

Edit

http://cgi.ebay.co.uk/VALEO-RADIATOR-88 ... dZViewItem

http://cgi.ebay.co.uk/CITROEN-BX-1-6-1- ... dZViewItem

Neil · Post by **Neil** » Mon Apr 30, 2007 5:27 pm

Thank you to all of you for your tips!

Best wishes from Neil

DLM · Post by **DLM** » Mon Apr 30, 2007 6:32 pm

While you're looking for a new one, it could be worth taking the rad out, turning it upside down and reverse-flushing. I removed a lot of gunk from a silted radiator that way, and it wouldn't do any harm to try a mild chemical flush - preferably one of the cheapie "one ingredient" suggestions like white vinegar or Jif. After all, if the rad is silted , think of all the coolant passageways inside the engine.

toddao · Post by **toddao** » Tue May 01, 2007 9:24 am

I've got similar issues with the added feature of an intermittant leak. Think it's blocked and squirts under load. Fan comes on late, if at all. Sometimes this is the connection to the switch and fan is re-animated with a shake of the connection.
What's the difference between the petrol and diesel radiators? I've got no idea where I'm going to get a new one from. I play it day to day and keep my eyes peeled for replacement.
Another thing, if the radiator is over-filled, what happens to the excess as there's no overflow? ( the manual stresses the min and max levels must be maintained)

Neil · Post by **Neil** » Tue May 01, 2007 9:28 am

There's a small hole under the filler cap on mine and the excess comes out there!

Best wishes from Neil

roscoe · Post by **roscoe** » Tue May 01, 2007 11:13 am

Diesel rads are thicker than petrol ones to provide more cooling area - double core vs single core. You often see them come up on ebay or failing that try Lockwoods or GSF in the UK who both handle new ones. Not sure where you'd find one in Germany, but both the above ship worldwide (I know because Lockwoods shipped me a TZD rad).

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