au1 xr8 heat issue

gra · 13-02-2013, 03:59 PM

hi all sorry if this seems as though its been asked before or even if it has i have searched and found some good info here but nothing that seems to relate fully to my problem here goes

i have an au1 xr8 sedan and under normal running the temp guage sits on the N even on a hot day however when i turn on the air con the oil pressure guage drops to zero (yes putting in for new sender and 15-40 oil had oil change done but think wrong oil used) but when this happens the temp goes to the M or A what i have noticed is only the passenger side fan seems to work from what i have read and i may have this wrong but 1 fan is for normal cooling and one is for aircon cooling when it starts to over heat i trun off the air con and withing a few minutes it cools down to the N now im thinking its the second fan fail thats causing this just bouncing from u guys to see if im on the right track
cheers in advance
gra

**auIILTD** · 14-02-2013, 05:28 PM

gra, if it is getting that high on the gauge, you should definitely have both fans running. I think you are on the right track. Easy enough to pull out and apply 12V to each to check them.

Not sure why oil pressure would be dropping though?

Best of luck with it.

Stu

gra · 14-02-2013, 11:21 PM

i have read on here that its a bit of a common problem where the wrong oil is used and a faulty sender unit usually ppl figure it out after they have an oil change done as was the case for mine even though i had not long prior brought the xr8 its clearly a faulty sender as was said previously if it were acurate the motor would be making a nasty loud noise and it clearly has oil and has it throughout motor the biggest problem i have is the interior fan stays on face no change to demister had a quote for $920 to fix it
anyways enough for now

cheers
gra

BHDOGS · 15-02-2013, 11:29 AM

Yeh oil senders are common problems with them check you fan relays
As I had a similar problem with my v8 and one of the relays was buggered and worked intermittently so was a tad hard to trace as for the climate control possible a broken rod if they quoted 920 I'm Assuming that's for them to take the dash out to fix it which can be done at home in about an hour.

dogphlap · 15-02-2013, 12:42 PM

Hi,

Are you sure the temperature is really going up and the oil pressure really goes low ?

It seems to me much more likely that you have an electrical problem (bad earth perhaps) that manifests itself when you turn on the air-conditioner i.e. you start drawing some current which results in a large voltage drop somewhere causing the symptoms you have. That is to say the gauges are lying to you due to a wiring fault.

Best regards

dogphlap · 15-02-2013, 02:06 PM

Hi again,

I have looked at the wiring diagram.
I don't think it is a bad earth.
I'd suggest you look at the internal fuse box (to the right of the steering column).
Look at fuse number 20 (which is a 10A fuse on my circuit).
If you have a volt meter check the voltage either side of the fuse (with respect to earth).
It should be around 12V. If it is less than 10V one side but not the other when the air con is on (you may need to run the motor at the same time while you measure this) you have either a high resistance fuse or bad fuse holder connections. That would be easy to fix with either a new fuse or a tension up of the socket spring contacts.

If the voltage is low both sides of the 10A fuse check the voltage at the 40A battery fusible link (under the bonnet). That is unlikely to be a problem because it feeds a lot more than just the 10A fuse so you would see more things not working correctly.

If you don't have a meter just change the 10A fuse and make sure the contacts grip the fuse properly.

I hope this helps.

Best regards

MrEL · 15-02-2013, 03:13 PM

I reckon its a bad earth.
Bad earths create all these annoying problems.

gra · 15-02-2013, 03:23 PM

hello all thanx for the replies the 920 that i was quoted was for the part apparently some door but not the one described in these forums apparently the aircon has to be degassed the dash removed then the aircon regassed afterward i just about fell over when told 920 clearly i only checked that the aircon was working when buying it and as it was blowing on me i knew there were no hoses fallen off as it would have gone to default of windscreen but i failed to fully test and i was not informed that anything was wrong with the interior fan when i brought the car only a few weeks ago as for the gauges ive thought that maybe the signal from the ecu may not be getting sent properly i have not seen any evidence to sugguest the car has been as hot as the gauge was saying

cheers
gra

dogphlap · 15-02-2013, 04:23 PM

Hi Gra,

With the ignition off:
Check the fuse.
Fuse 21 is the red fuse on the bottom row at the right hand end (the cream plastic is marked 21) in the interior fuse box.
Take out fuse 20 (immediatly to the left of 21) and put it somewhere you won't loose it.
Take out fuse 21 and put it into fuse 20's place.
Try it.

FYI fuse 21 is the air bag fuse. If this solves the problem don't travel far before replacing that fuse with a good one. Obviously if nothing improves just put the 10A fuse back (both fuses should be red 10A fuses).

Zero cost and 5 minutes of your time.

As to poor earths:
When I look at the circuit a poor earth to the instrument cluster and or the microprocessor assosiated with it could cause your problems I guess (somewhere in there would be a voltage regulator for the electronics and instruments that would not enjoy a poor earth either). Still I'd check the fuse first as above, easy and cost free to check by substitution.

Best regards

gra · 17-02-2013, 11:07 AM

hello all well ive checked the fuse and a mixed report the gauges were moving and responding in different ways than before but only for the worse
the oil pressure gauge did not go above half way however every time i turned a corner it dropped to 1 and sitting at lights idling also a 1 and as soon as i turned on air con went into red the battery gauge was sitting on 14 but went up as high as 15 not much to report on temp gauge as ambient temp was not high however 2nd fan still not working and all gauges seemed to move up more gradually then before from a cold start am now wondering if maybe the ecu is completely haywire am thinking about trading it in for something i can resell the more time i have this the more repairs it needs

**auIILTD** · 17-02-2013, 06:09 PM

gra, highly unlikely that it is the ECU. Have you managed to measure the voltage across the battery with the engine running, and revved. One thought is that it may be regulator in your alternator. As mentioned above, bad earths can cause some funny symptoms, so can high voltage, which unregulated will be all over the place with revs and electrical load.

With your oil pressure sender, they are really only an on / off indicator. Usually your gauge will sit at around 3/4. Varying voltages may cause the gauge to show other results.

You should not be seeing anything higher than about 14.2V across the battery terminals. If it is going higher, also check your battery fluid levels. High voltages will cook your battery.

Stu

gra · 02-03-2013, 10:00 PM

hello all well a mixed update
i was told that it could be the battery (as when i went to look at the car prior to purchase it had a flat battery that they guy had to recharge) so i have swapped the battery and the under bonnett fuses and relays for fans and now the second fan is working (have seen it working) (need to know which fan it is on drivers side of radiator fan 1,2 or 3) early days of testing but so far the oil pressure will drop down to the first white line but so far has not dropped to zero and beeped at me the temp gauge is sitting plum on the N mark so nice and cool and the amp meter is now sitting a hairline under 14 or a hairline over 14 or dead on 14 so not sure what to make of all that so far but testing continues (until the other person realises and wants their battery and fuses back lol .... just kidding they know ive got them lol)
cheers
gra

gra · 08-03-2013, 11:48 PM

hello all well heat issue sorted was the no.1 fan relay now both fans are working it sits nice and cool on the N

cheers
gra

AUFanboy · 10-03-2013, 02:48 PM

Sounds like the battery helped but I'd still recommend going to supercheap auto and buying one of their big fat ground cables with pre-crimped connectors. Run it from one of the alternator mount bolts to somewhere on the body. This makes the gauges work much better, no more dropping oil pressure when you turn the headlights on etc. Common problem on e-series and AU1, they changed the gauges to fake ones in the AU2 for this reason.

Did this on my old EL and the gauges were actaully very accurate afterwards. Makes the headlights brighter too.