another issue...
Discussion
The temp gague used to be pretty believable, with the fans coming on around the 100 mark on the gague or so, with the needle climbing, leveling off as the fans came in, dropping, until the fans went off again, and so on. But now, either the fans are not coming on, or the gague has decided to start playing up.
I'm a bit loath to just leave the car and see if the fans do come on, as I won't know how hot the car is getting, or indeed, if it's getting too hot.
Also, the gague uses a capilary action, yes? This would suggest that the gague should slowly creep up the scale as the pressure in the tube increases with heat, however, today I noticed the gague suddenly jump and then settle back, as if pressure was building up somewhere else, being released at the gague, and then settling down again. It jumped from around 90 to over 110 and back in a second or so. I don't think it should be capable of that if it was working correctly, should it?
So... do we think the fans have given up the ghost, or are we suspecting that the gague is temperaturely challenged and the fans would probably be OK?
Is there any easy way to test whether the fans are working correctly? or any way of getting a more accurate reading of the correct temp?
I've checked the fuses, and they seem fine. The relays look OK, but I don't suppose they would show any signs of being dead anyway.
I'm a bit loath to just leave the car and see if the fans do come on, as I won't know how hot the car is getting, or indeed, if it's getting too hot.
Also, the gague uses a capilary action, yes? This would suggest that the gague should slowly creep up the scale as the pressure in the tube increases with heat, however, today I noticed the gague suddenly jump and then settle back, as if pressure was building up somewhere else, being released at the gague, and then settling down again. It jumped from around 90 to over 110 and back in a second or so. I don't think it should be capable of that if it was working correctly, should it?
So... do we think the fans have given up the ghost, or are we suspecting that the gague is temperaturely challenged and the fans would probably be OK?
Is there any easy way to test whether the fans are working correctly? or any way of getting a more accurate reading of the correct temp?
I've checked the fuses, and they seem fine. The relays look OK, but I don't suppose they would show any signs of being dead anyway.
Edited by volospian on Friday 29th February 17:22
Brummmie said:
A lap top with the ECU software will give you correct temperature. You could put 12v direct to the fans to test the motors.
Yeah, I may need to wait until next week when I can take it in to Paul at PPC. I don't got the software 
I was thinking of testing the fans direct, it'll at least let me know that they are actually functioning.
BLEED the sytem - Takes 2 minutes, do it with the engine cold. This is something that should be done regularly on the AJP V8, very important, and should be the first thing you do as soon as you notice anything untoward with the cooling system, the needle suddenly jumping up like that is your engine saying "Bleed me!"
JensenA said:
BLEED the sytem - Takes 2 minutes, do it with the engine cold. This is something that should be done regularly on the AJP V8, very important, and should be the first thing you do as soon as you notice anything untoward with the cooling system, the needle suddenly jumping up like that is your engine saying "Bleed me!"
I'll bleed it tomorrow then.Yep, then warmed the car for a bit and re-bled the lot.
I took it for a drive after and let it get (indicated on the gague) quite hot, to see if it was sorted, with no joy. However, I'll try bleeding again now in case the drive has moved an airlock or something.
My guess is that, as the front of the header is blowing, it's heating the capillary up, which is causing a false reading, and that the system is probably OK.
If I can find some resistors I'll knock up a cable and try and see what the engine thinks the temps are. It's the only way I can be sure, really. Otherwise it's all just guesswork and assumptions.
I took it for a drive after and let it get (indicated on the gague) quite hot, to see if it was sorted, with no joy. However, I'll try bleeding again now in case the drive has moved an airlock or something.
My guess is that, as the front of the header is blowing, it's heating the capillary up, which is causing a false reading, and that the system is probably OK.
If I can find some resistors I'll knock up a cable and try and see what the engine thinks the temps are. It's the only way I can be sure, really. Otherwise it's all just guesswork and assumptions.
Just in case (i'm sure you have done it correctly).
Its best to bleed the system with the car's nose slightly up, ie front higher thn tha back.
Undo the header tank cap and fill it.
Undo the bolt on the radiator, if no water comes out, remove it and fill with water through this hole till water runs out.
The undo each bleed tap an the water rails until water comes out.
If you've got a good set of lungs and bif wide mouth, whn one of the bleed nipples areloose, put your mouth over the header tank opening and a good give short sharp blow, your neighbours may think your giving the car a BJ, but so what, you do love her
.
As for finding the correct Temperature, just hook it up to a laptop, All you need is a laptop with a serial port, the s'ware which is freen from Byker28i, and a normal serial cable from maplins/PC world.
Its best to bleed the system with the car's nose slightly up, ie front higher thn tha back.
Undo the header tank cap and fill it.
Undo the bolt on the radiator, if no water comes out, remove it and fill with water through this hole till water runs out.
The undo each bleed tap an the water rails until water comes out.
If you've got a good set of lungs and bif wide mouth, whn one of the bleed nipples areloose, put your mouth over the header tank opening and a good give short sharp blow, your neighbours may think your giving the car a BJ, but so what, you do love her
.As for finding the correct Temperature, just hook it up to a laptop, All you need is a laptop with a serial port, the s'ware which is freen from Byker28i, and a normal serial cable from maplins/PC world.
Yep, that's what I did. I had searched before and found a post (from yourself, actually) detailing the bleed method before.
The gauge needle doesn't flap around anymore (at least it didn't when I took it out on Sat) but the fans still hadn't come on when the gauge was showing nigh on 110, used to come on while showing around 105, and go off when it was just under 95 or so.
I didn't realise it just needs a straight serial cable. I have stacks of them lying around at work. I saw a diagram on the website with the software and it had a few resistors in the loop.
The gauge needle doesn't flap around anymore (at least it didn't when I took it out on Sat) but the fans still hadn't come on when the gauge was showing nigh on 110, used to come on while showing around 105, and go off when it was just under 95 or so.
I didn't realise it just needs a straight serial cable. I have stacks of them lying around at work. I saw a diagram on the website with the software and it had a few resistors in the loop.
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