Heh... 1 hour in a traffic jam -> overheating engine

citronut · Post by **citronut** » Mon Jun 29, 2009 11:26 am

this is why head bolts are tightened down useing angular tightenning ratter than torque tightenning these day,

also if the head job is done corectly/thoroughly it can cost 5 to 6 hundred by a good indy

regards malcolm

TB2 · Post by **TB2** » Mon Jun 29, 2009 12:53 pm

Yeah I believe that, had a blown head gasket on a 1.0l Suzuki Swift once. It cost a fortune to do the job but I was out of options at that time.

Today I had a look at the fallen off fan. For some reason the screw in the middle was missing!

Well, found a fitting one and reattached it, looks like new. Didn't have a chance yet to check the fuses or if that one fan is turning again although I had to pick up a table a few km away and again I experienced a smooth ride.

Although... Right after starting the engine, I tried rev'ing it a little bit to like 1500rpm to watch out for odd coloured smoke. Well, it looked like usual, no visible fumes while pushing the throttle, and a hint white-ish smoke when releasing, but it's always been like that right after ignition, guessed it's due to the engine being cold. What I noticed is that everytime I released the pedal, there was a bit of a clickery sound for a second somewhere from the engine. I tried operating the throttle manually and listened closely to locate the noise but I wasn't able to. It could have been coming from the alternator region, but I'm not sure at all. The noise almost went away after a minute or so and I didn't hear it after that, again guessing that it's got something to do with the engine being cold.

So what colour would the fumes usually have if the head gasket is obviously blown?

toddao · Post by **toddao** » Mon Jun 29, 2009 1:00 pm

I just checked my twin fans this morning after reading this.

They both come on at the lower speed setting but only one at the high speed. I swapped the relays over and there was no difference. Can anyone suggest what this might be?
I'm not overly concerned as my other BX only has one fan and I think the reason that there's two fans on the TRD is that it was used for towing a caravan.

The head gasket can be done quite cheaply though it's obviously a pain in the area. It's the labour that makes it expensive I suppose.
When I did mine the bolts were €25, the gasket 1 quid from The National (though normally another €25), all the cam oil seals etc another €20, skimming the head €60. That's a total of.. approx €100, though the head should also be pressure tested really.
Fingers crossed Carl that you've escaped the experience!

prm · Post by **prm** » Mon Jun 29, 2009 2:38 pm

Todd

With your loss of high speed on both fans, it could be the supply/connection to the relay coil on 773.

Not sure as to your exact set up, but a twin fan drawing that may help.

http://i295.photobucket.com/albums/mm15 ... fans_1.jpg

Regards

toddao · Post by **toddao** » Mon Jun 29, 2009 4:05 pm

Thanks, Prm, another one of your excellent diagrams! I've also got the thermostat/ switch set up that you advised installed now : 81 degree 'stat and 79 degree fan switch and it works very well.

citronut · Post by **citronut** » Mon Jun 29, 2009 8:38 pm

the usual sign of a head gasket on these PSA diesel lumps is coolant eruptting out of the rad/header tank cap with cap removed, if its realy bad it will do this whilst crancking it over stone cold

regards malcolm

prm · Post by **prm** » Mon Jun 29, 2009 11:37 pm

Another mod I’ve added to the 16v, is replacing the light of death temp switch/sender @ 110° with the lower high temp switch/sender @105°C.

Gives you an earlier warning, with the red stop/warning lights visible, as I could never easily spot the small yellow/orange dash warning light as TZD,s

Correct me if I’m wrong. I seem to remember that MK1’s???, at some time, had audio buzzers or flasher units fitted into the lower temp 105° circuits.

Any members BX’s have this fitted??
Would be grateful, if poss, the make and number on this unit.

Many thanks.

Regards

Jaba · Post by **Jaba** » Tue Jun 30, 2009 1:18 am

toddao wrote:I just checked my twin fans this morning after reading this.

They both come on at the lower speed setting but only one at the high speed. I swapped the relays over and there was no difference. Can anyone suggest what this might be?

Todd, how did you check the fans ? If you just short the hispeed lead to earth at the radswitch only the lh fan will run. You have to short both low and high speed leads to get stereo fans at high speed.

Jaba · Post by **Jaba** » Tue Jun 30, 2009 1:31 am

prm wrote: Correct me if I’m wrong. I seem to remember that MK1’s???, at some time, had audio buzzers or flasher units fitted into the lower temp 105° circuits.

Pete, yes I had a Mk1 GTi with a winking low temperature light. Wish I had kept the flasher when I scrapped it. You could always fit a warning buzzer I suppose.

BTW I was moved by your earlier schematic of wiring mods to fit low speed and high speed fans warning lights to my TD. The aircon was working perfectly before I did this.
The aircon responded in typical fashion by never getting up to pressure and never switching off the fans and compressor. Looks like most of the R12 has finally leaked out as the cooled air temperature never gets below 10deg.

prm · Post by **prm** » Tue Jun 30, 2009 8:20 pm

Jaba

If your AC charge pressure is bordering on the 3bar mark, it can sometimes fool you into a fully operational state, especially with the current hot weather.

Had this with a TZI with AC. As the engine warmed up stationary, this would heat the remaining refrigerant and dryer, trip the dryer pressure switch and run the compressor for a short while when actuated, but fail to operate first thing from cold.

Both fans will run at any time at slow speed, with AC switched on, with no charge pressure ( believe I mentioned high speed in a recent post – correction- slow speed, an age thing!!) As the air con main relay is linked into the input on the lower temp side of the rad switch, and bridges the twin fan circuit direct to earth/negative.

Many thanks for info on temp light flasher.

Found a sounder at Maplins, with a choice of tunes.
Yellow rose of Texas
Dixieland
Red river valley
American patrol
Oh my darling clementine
When the saints go marching in
She wore a yellow ribbon
………………….
What tune do you think would be appropriate before you say, “OH SH-T”

Regards

Pete

TB2 · Post by **TB2** » Tue Jun 30, 2009 9:13 pm

prm wrote:Both fans will run at any time at slow speed, with AC switched on, with no charge pressure ( believe I mentioned high speed in a recent post – correction- slow speed, an age thing!!)

Uhm, I'm not sure I understand, does this mean that although my AC is flat, if I turn the switch, both fans should kick in?

On the BX DIY page says it's like this:
- High Temp + AC off = One fan turns fast
- High Temp + AC on = Both fans turn fast
- Mid Temp = Both fans turn slowly
- Low Temp = Fans don't turn.

But what about
- Mid Temp + AC on or off? Any difference or "both fans turning slowly" in both cases?
- Low Temp + AC on = Fans switched off or slowly turning?

I had a look at the relay today and it's clicking (also tried switching it with one of the right ones, it's the same). They were not turning on after about 7 Minutes of idling, and the coolant distributor at the top of the engine was very hot to the touch so I turned the engine off. Not sure if the fans should have kicked in. I also attempted to try jumping the temp sensor cables but the sensor is in a place not reachable without removing the air intake hose and such, I'll do that tomorrow when at the garage...

Post by **mat_fenwick** » Tue Jun 30, 2009 9:30 pm

TB2 wrote:although my AC is flat, if I turn the switch, both fans should kick in?

Yes. If your set up is the same as mine, and the same as the wiring diagram I have the situation should be as follows:
Engine normal temperature, A/C off - no fans
Engine normal temperature, A/C on - both fans slow (regardless of whether A/C works...)
Engine hot, A/C off - both fans slow
Engine hot, A/C on - both fans slow
Engine very hot, and/or A/C high pressure - both fans fast

prm · Post by **prm** » Tue Jun 30, 2009 10:03 pm

I agree with Mat.

I think initially, you need to view the cooling and AC systems as two independent circuits linked by the AC main relay, and the layout of your existing wiring.

Most problems seem to arise from the rad temp switch connections.

The original 3 pin connection block on the temp switch has sometimes been replaced with individual spade connections and fitted incorrectly.

I would disagree with the DIY page first scenario of.
High Temp-AC Off = one fan on high speed.

What’s the point of having just one fan on at high speed when the cooling system is calling for maximum air throughput, and then, transfer the circuits, to operate both fans at slow speed with the lower temp rad switch position.

Without viewing the DIY electrical diagrams, I’m not sure how you would easily separate the single fan, -high temp,-high speed operation from the AC twin fan system set up, but I stand to be educated.

Regards

Jaba · Post by **Jaba** » Tue Jun 30, 2009 11:15 pm

TB2 wrote: Uhm, I'm not sure I understand, does this mean that although my AC is flat, if I turn the switch, both fans should kick in?

Precisely. We are beginning to go around the houses here. You have no fans running at low speed with a/c on and only one fan when the engine coolant temperature calls for high speed fans.
See my earlier post which describes the likely cause. Have you checked the fuses, start with F4.

TB2 · Post by **TB2** » Tue Jun 30, 2009 11:31 pm

Yeah I checked all the fuses and the relay as I said in my previous post (also swapped the relays). I'm going to do this tomorrow:

DIY guide wrote:To check the high speed, touch the green wire to some exposed metal part: with the A/C on, both fans should run in high speed, without the A/C only one of them. To check the low speed, touch one of the blue wires to earth (if nothing happens, try the other blue wire): both fans should run in low speed.

I wanted to do it today but here I haven't got the proper tools, and the temp sensor is really hard to get to without jacking up the car and going under it, or removing the air intake hose at the top.