Overheating

Gents,
Stuck again with a limited photo copy of a workshop manual, I have just swopped out the front radiator and have learnt the hard way to follow the manual and remove the bumper first, the temp gauge still rises over 90 degrees quite happily further helped by another new problem of a non functioning engine cooling fan, I have checked the fan and this is OK and has power to the red cable. The manual diagram mentions two relays that do the controlling for the time and temperature facility which worked really well until I did some engine detailing, my question is where are the relays located and where can you get replacements as Simon no longer lists them.
I would be grateful for any advice as I long for a trouble free trip to join in your events but I need the reliability.
Regards

.

Stuck again with a limited photo copy of a workshop manual, I have just swopped out the front radiator

Hi there,
There are quite a few questions I would like to ask so as we know exactly where you are coming from
Firstly, the rad that you fitted .... is it exactly the same as the OE one or was it different ...... and if different has it got the bleed pipe coming off the top as in the OE one? Also, have you refitted the air scoop and is it a snug fit up against the rad ?

..... another new problem of a non functioning engine cooling fan, ............ The manual diagram mentions two relays that do the controlling for the time and temperature facility

First question .... has your Alp got Air con ? ...... and when you talk about the "engine cooling fan" ....... if it is the Atmo Engine Bay Cooling fan,...... there are no relays involved. That fan is controlled only by the Bi Metallic thermoswitch mounted on the near side heat shield.
However, if it the Rad cooling fan/s you are talking about (2 x fans for A/C, and 1 x for non A/C) Then Non A/C, .... 1 x relay, and A/C .....3 x relays..
Sorry about all the questions but clearly we must be on the same page as you.

Martin,
Many thanks for the note, would very much like to meet up when you have recovered, I live in Biddenham on the west side of Bedford.
I have checked the thermostat by cooking in a pan of hot water and appears to operate OK. I have some experience with classic cars but so far I am stumped with these overheating issues.

John,
Again thanks for the response,
Car is a GTA atmos, no aircon but remanants of air con or power steering pipe work above front rad crossmember.
Replacement radiator came from Big MV and looks identical to old one, in fact both rads seem to be in good order with no signs of blockages, bleed pipe hangs down from top of rad, No cowling in sight if it is the same one shown on the Simon drawing.

My issue is the rear engine cooling fan, however static tests as the car is SORNed at present a very hot inlet and return pipes when going and coming from the front rad with the rad fan on, which works OK with the rad thermostat but not a huge difference in temp from one side of the radiator to the other.
Could the front to rear pipes be blocked, I resisted disconnecting from engine and putting the hose on to flush through as all joints seemed sound and settled, when I first the drained coolant from the front rad end it was an unhealthy heavy rust colour, then refilled with water and the Holts rad flush kit applied, reflushed via the expansion tank and finally new antifreeze mix with the car on a slope and bled for airlocks.

I seem to have all the extra heat sensitive switches on the engine block according to Simon parts drawings which did offer the time delays for different temps when the engine fan was working.
I may have a bit of a mongrel here perhaps.

Regards

............. No cowling in sight if it is the same one shown on the Simon drawing.

If you are telling me that there is no scoop/cowling fitted ....... there is your problem. ....... the scoop in these Alps is just as important as the radiator itself. If you think about it, the air comes in at low level through the grill below the numberplate. It then travels up the front of the rad and we are asking the air to turn through 90 degrees to pass through the rad. If the scoop is not in place, the air will take the easiest route to escape, which will be to spill out sideways into the wheel arches with very little taking the 90 degree route through the rad.
The scoop is quite a clever unit. It has a fairly small air entry area at its "mouth", opening up into a much larger void enclosed by the scoop. With the scoop tight up against the rad and "roof of the void" panel, the collected air will not be able to spill out and as a consequence, as pressure builds up in the void, the air will be forced down through the rad effectively cooling the coolant.
The fairly small area of the scoops "mouth" acts as a non return valve as the air pressure builds up in the void, and does not allow the air to escape back out through the "mouth" due to the ram effect of the air coming in, which therefore causes all the air to be forced through the rad.
Next job ....... get hold of a scoop.

I seem to have all the extra heat sensitive switches on the engine block according to Simon parts drawings which did offer the time delays for different temps when the engine fan was working.

For some reason you seem to have some heat sensitive switches that are not OE ....... any chance of a pic showing the switches in their positions.
As I said before, in an Atmo Alp, there is no timed switches for different temperatures, just one heat sensitive thermoswitch mounted at the rear of the nearside heat shield covering the manifold. Once the fan is running, as the Engine bay temperature cools and reaches its switching point, it shuts off the fan. It is wired directly (via fuse) to the battery, so it keeps running even when the ign is switched off.
I hope this is of help to you ........... BTW, have you thought of becoming a full member as there are many useful tips to be had in the RAOC Members Area.

[BIG_MVS]

Have you tried bridging the two wires for the sensor to test the fan?

I have a Rad Fan Scoop, needs a bit of tlc but it will be better than no scoop at all! Let me know if you are interested in it.

The engine bay cooling fan is really an anti-perc fan, it's not designed to keep the engine cool per-se, that's the job of the liquid cooling system. Point being even on the turbo, it's not essential to have the rear fans working. (It's not ideal, but the car shouldn't overheat, certainly not on the move - they're there to aid starting and keep the components cooler when stuck in traffic. Yes you want the fan to work but if it wasn't functioning on a journey it shouldn't leave you stranded)

As John rightly points out, the rad cowling is essential. You lose so much airflow without it in place and at higher speed you just can't get the air through.

Equally important though at low speed and when stopped in traffic is that the front rad fan is working properly. That will take over when it needs to, so is that functioning and sucking (or blowing) air through? (Most cars have a suction fan, but I think the arrangement was reversed on some of the air-con cars with the motor front mounted and configured to blow through the core)

.

Gents,
Thanks for all the feedback which all sounds very logical and is improving my understanding of the GTA.

I will contact BIG_MV re his offer of a cowl and will also attempt a wiring check from the engine fan which does operate when earthed to the rocker box.
Following John's advice the heat shield sensor is clearly identified so I will focus on the wiring from this to the engine fan because this seems to fit best how the fan used to operate when the engine was switched off.

Bye for now

Bye for now

I guess you'll be back as a member?

Simon,
Hopefully, but I found the membership application tricky about a year ago with my limited IT skills and changes with the RAOC, both have now evolved and will try again. The clubs French trips are tempting for a GTA owner.
Regards