Overheating

Post by **mat_fenwick** » Tue Jul 12, 2011 10:22 am

Gibbo2286 wrote:It seems to me that you haven't actually got an overheating problem just a gauge mis-informing you.

Not so sure personally - I would expect the fan to come on after being stationary for a while, and if there was a gauge problem I wouldn't expect it to read normal in normal use. I had missed the bit about the heater not getting warm though, which could be down to a restriction in the flow to it. Can you hold the hoses in the engine bay when the gauge says the engine is warm?

Gibbo2286 · Post by **Gibbo2286** » Tue Jul 12, 2011 10:36 am

mat_fenwick wrote:
Gibbo2286 wrote:It seems to me that you haven't actually got an overheating problem just a gauge mis-informing you.
Not so sure personally - I would expect the fan to come on after being stationary for a while, and if there was a gauge problem I wouldn't expect it to read normal in normal use. I had missed the bit about the heater not getting warm though, which could be down to a restriction in the flow to it. Can you hold the hoses in the engine bay when the gauge says the engine is warm?

If it was overheating to the extent that it's in the red on the gauge I'd expect it to boil, in my experience the fans hardly ever come on on BXs even when left ticking over for an age. Gibbo.

RobC · Post by **RobC** » Tue Jul 12, 2011 10:51 am

Gibbo2286 wrote:
mat_fenwick wrote:
Gibbo2286 wrote:It seems to me that you haven't actually got an overheating problem just a gauge mis-informing you.
Not so sure personally - I would expect the fan to come on after being stationary for a while, and if there was a gauge problem I wouldn't expect it to read normal in normal use. I had missed the bit about the heater not getting warm though, which could be down to a restriction in the flow to it. Can you hold the hoses in the engine bay when the gauge says the engine is warm?
If it was overheating to the extent that it's in the red on the gauge I'd expect it to boil, in my experience the fans hardly ever come on on BXs even when left ticking over for an age. Gibbo.

With the utmost respect, this is incredibly dangerous talk. The OP has a 16v, remember. These things get very hot very quickly. The original fit cooling systems to 16v was never sufficient anyway - one fan on one side of a tiny radiator. Many 16v owners have, over the years, fitted 2 fans and/or a lower cut-in switch from a diesel.

He also recounted that both the gauge was in the red and the red warning light was on - on the 16v there are separate sender units on the engine for both the gauge and the warning light which are right by the thermostat housing so I would say it's pretty much guaranteed that his engine was overheating.

IMHO it's an overheated engine caused by a failed fan thermo switch (due to fuse/dodgy wiring/failed switch, whatever, as others have surmised).

rayfenwick · Post by **rayfenwick** » Tue Jul 12, 2011 11:12 am

I have to agree with RobC on this one - err on the side of caution when it comes to an overheating issue - especially with an engine as prone to damage and head gasket failure as the 16v.

If the gauge/warning light is telling you a car is overheating when you *know* it's stone cold then by all means you can focus firmly on faulty gauges/senders etc, but when the engine *IS* hot, then I'd want to be very sure before I made such an assumption.

As others have said, and the way I did it:
make sure the fan is not seized and will turn by hand
replace the fan fuse(s)
short out the fan switch and make sure the fan runs. If it doesn't:
check the plug(s) in the circuit (where my CX 22TRS failed)
run direct wires from the battery to the fan to make sure the fan itself works(make sure you use thick enough wire, or it melts and burns your hands...)

It's a matter of being systematical and eliminating each component in turn. Good luck, and let us know how you get on.

mds141 · Post by **mds141** » Tue Jul 12, 2011 6:17 pm

Hope i haven't started an interstellar war on this here forum

Dropped car off at Dave Asworth's in Blackpool[Citroen specialist]. On way down the A6 and M55 temp gauge stayed at 80 degrees whilst in motion rising slowly at standstill[sounds like shipping forecast] hot air now flowing out of vents as per but still no fan operation. Would rather err on the side of caution and let an expert look at it. Thanks for all the input guys. With luck will be attending the National in the BX.

BTW one here for Tim, is there a jet wash close to the Skylark showground

Philip Chidlow · Post by **Philip Chidlow** » Tue Jul 12, 2011 6:22 pm

mds141 wrote:BTW one here for Tim, is there a jet wash close to the Skylark showground

Excellent. (Because I doubt I'll have time to clean the car beforehand!)

mds141 · Post by **mds141** » Tue Jul 12, 2011 6:45 pm

Mind you knowing Tim, he'll probably be bringing his own jet wash

Post by **Tim Leech** » Tue Jul 12, 2011 10:30 pm

mds141 wrote:Mind you knowing Tim, he'll probably be bringing his own jet wash

Haha NO, I will be bringing sponges, buckets, polish and chamois leathers though......as I expect will you!

Gibbo2286 · Post by **Gibbo2286** » Wed Jul 13, 2011 8:40 am

RobC wrote:
Gibbo2286 wrote:
mat_fenwick wrote: Not so sure personally - I would expect the fan to come on after being stationary for a while, and if there was a gauge problem I wouldn't expect it to read normal in normal use. I had missed the bit about the heater not getting warm though, which could be down to a restriction in the flow to it. Can you hold the hoses in the engine bay when the gauge says the engine is warm?
If it was overheating to the extent that it's in the red on the gauge I'd expect it to boil, in my experience the fans hardly ever come on on BXs even when left ticking over for an age. Gibbo.
With the utmost respect, this is incredibly dangerous talk. The OP has a 16v, remember. These things get very hot very quickly. The original fit cooling systems to 16v was never sufficient anyway - one fan on one side of a tiny radiator. Many 16v owners have, over the years, fitted 2 fans and/or a lower cut-in switch from a diesel.

He also recounted that both the gauge was in the red and the red warning light was on - on the 16v there are separate sender units on the engine for both the gauge and the warning light which are right by the thermostat housing so I would say it's pretty much guaranteed that his engine was overheating.

IMHO it's an overheated engine caused by a failed fan thermo switch (due to fuse/dodgy wiring/failed switch, whatever, as others have surmised).

That is of course what I said in my first reply, I assumed that he'd already tested out that theory as he was going immediately out to do the tests I'd suggested.

mds141 · Post by **mds141** » Wed Jul 13, 2011 8:05 pm

Problem solved you may be relieved to know. New thermo switch and contacts for fan dipped in acid solution. Fan kicks in at around 95 degrees. Thanks for all the advice.

RobC · Post by **RobC** » Wed Jul 13, 2011 8:17 pm

Good news, glad to hear it.

Gibbo: apologies, i waded in a bit late without checking back!

Rob

rayfenwick · Post by **rayfenwick** » Thu Jul 14, 2011 1:04 am

Guilty of the same sin as RobC - sorry Gibbo,