Volvo 480 Club Europe

Come to think of it even after I brimmed the tank the fuel gauge was only showing about three quarters. Could that and an under reading temp gauge suggest a volt drop to the gauges?

I understand this is a common problem with that gauge unit and I had it on my 440 - very slow fuel gauge, never got above halfway, and random temp gauge readings.

The gauge unit is mounted onto the PCB on 4 metal "washers" and these provide the earth for the gauges. But they tarnish...

If you strip the instrument cluster down and remove the gauge unit I suspect that is what you will find. They were very bad on my 440.

Clean up, reassemble, and hopefully you'll see an improvement!

On the 440 my temp gauge now work properly and the fuel gauge, although it still takes a few seconds to rise, shows a full tank when the tank is full

But I doubt that's the answer to your fan kicking in more often than you expected. That is more likely down to low coolant level as you note you have, or even the temp sensor for the fan failing (or perhaps just needing a clean if there has been no coolant change for a while).

Hope that helps!

David

Hello and welcome.

All of what David said is worth bearing in mind, as the extra resistances could affect the readings on the info centre.

One more thing to bear in mind is that the designers of the 480 were very cautious and have made it so the cooling fan comes on a lot after switching the engine off, especially the later cars I found.

Next time you brim the tank, give it a little while to react and then put the ignition on while holding the grey button of the Info Centre down. This way you can see what the tank thinks that it has in it. I think you can get it do display Ohms and Litres. This can then be adjusted with the potentiometer which is hidden under the tiny black between the two grey Info Centre buttons.

Of course, there is no point in adjusting if there is a high resistance lurking somewhere… this should be fixed first!

I saw your thing about a sniffer and also recently on AS mentioned one of these, to do it yourself at home if you fancy: https://www.ebay.co.uk/itm/Combustion-l ... 635-2958-0

It’s an S James! No info centre!

Oh, yeah. Disregard my ramblings Sunny Jim!

No worries James, I'm a base model kind of a guy! Had a 40 mile run out along the A5 to meet up with a friend who has a 740 this afternoon.


During the trip I kept an eye on temps and levels and although the temp gauge didn't raise too much I'm losing coolant at the rate of about half a litre an hour on a run but I've still can't see where from. I'm pretty sure both the temperature gauge and the fuel gauge are under reading which indicates a volt drop to both. David tells me that they're grounded through metal washers which are likely to have tarnished so I'll have to take the instrument pod apart and clean those.

I'm now fairly confident that I'm not running hot per se and that the temp light coming on on Saturday was due to low coolant levels. Sniff test kit I've ordered should be arriving next week which I can do myself but if I haven't found the leak by then I'll pay someone to pressure test it. A coolant change and new thermostat are still on the list but the timing belt is due so I might as well get a new water pump while I'm at it.

Pressure testing kits are quite affordable these days. I'd argue a more useful tool that a sniff kit!

Not had much time to devote to the 480 recently but I did get a chance to do the "sniff" test today and I'm relieved that there appears to be no problems with the gasket, head or block - still not sure where the coolant leak is though. I'm losing between 1/4 and 1/2 litre per hour when running so I guess the next stage is a pressure test.



It also appears that I haven't yet solved my electrical problems. When parked up the passenger door locks and unlocks itself turning on the interior light every couple of minutes. It first did this last Sunday after an hours drive to visit a friend. When I drove home it didn't do it again so I naively hoped it was cured. A couple of nights later when letting the dog out I noticed the interior light was on again so I pulled the number 8 fuse which does the central locking.

I wanted to drive the car today so put the fuse back in and immediately there was a clicking noise (like the indicator warning but quicker - incidently the noise slowed down when using the indicators) and a beep when I started the car although it ran fine. It's also displaying a couple of warning lights - door open (although I double checked they were all shut) and rear heated screen on (although it wasn't!). Disconnecting the battery and leaving it for an hour solved the problem temporarily. Later I went to Halfords to buy a few bits and the central locking worked and the car stayed locked while I was in the store. The car started fine so I drove home but when I arrived and switched off the clicking started again. Aghh! Intermittent problems are so frustrating.

I've disconnected the battery again for now and will run a diagnostic on the CEM when I get a chance.

Hmm, not sure the diagnostics on the CEM is smart enough to tell you much.

How about you pop the internal door lock covers off and give a squirt with contact cleaner— just in case the micro switches in there are giving trouble? The same with the actual latching part on the door (that’s where the door open switches are).

If not, maybe it is a CEM repair job required.


Have you felt the floor for a leaking heater matrix? It lives behind the centre console, near the floor, between the two foot wells.

For the coolant loss, check for rusty looking hose clamps. The other one I’ve had is the 90 degree bleeder from the top of the rad.

Hmmm...sorry, it sounds as if the CEM isn't as fault free as I thought. I'd connected up to test, it all seemed OK...

Central locking, clicking and beeping and the warning lights you mentioned all point to the CEM

David

Thanks James, Jeff and David. I've a busy week coming up but I'll try out your suggestions when I get a chance next weekend.

Sunny Jim wrote: ↑

Sun Jul 04, 2021 5:24 am

Come to think of it even after I brimmed the tank the fuel gauge was only showing about three quarters. Could that and an under reading temp gauge suggest a volt drop to the gauges?

I have worked on a car with gauges instead of infocentre yesterday. Could not get anything working. Resorting to changing the entire instrument cluster to one with infocentre and found the weirdest behaviour. With ignition on, everything worked fine. Upon starting the engine, the infocentre went blank.

After 2 hours of measuring and changing stuff (changed the instrument cluster, changed the infocentre computer) I decided to check the alternator. And lo behold, there was my problem:



The blue-brown wire is ground of the electronics which display the sensor readings (fuel, temperatures) for interference) reasons. If you disonnect this wire, the speedometer and rev counter will remain functional, but gauges or infocentre will stop working.

Apparently, someone changed the alternator, found a dangling wire and figured it needed to be connected to D+ of the alternator.
Which is grounded when the alternator is not charging, because this is how the charging light is lit. But once the alternator starts charging, the voltage rises on this terminal and will not be enough to power the electronics in the instrument cluster.

So I connected the blue-brown wire to one of the bolts of the alternator, which is ground.



And there was much rejoicing!

Good Catch

Thanks for the clear explanation and photos Brinkie, I'll check my alternator connections before I start taking the dash apart.

I nearly bought this one but the seller wouldn't go below 2500 so I bought my GT for 2450 instead.

How much did you pay for it if you don't mind me asking?

Got some tinkering time in this afternoon to try and find the source of my coolant leak. I'd picked up some ramps off FB marketplace for a tenner so after checking they were ok got the front of the car in the air and removed the under tray.


The leak is obviously coming from the right hand side of the engine - it's also obvious I'm going to have to spend some time with a wire brush and rust cure before the winter looking at the underside of the car.

Back down off the ramps I jacked the front offside of the car and removed the wheel and inspection panel.


Bingo! It's the water pump. The timing belt was last done in 2015 at 66k (currently on 82k) so I'll do that while I'm at it.


Can anyone provide part numbers and recommendations for brands and suppliers please? I don't mind paying slightly more than the cheapest eBay price if it helps support a business that's useful to the 480 community.

Ah, a nice easy spot!

So, First off, the parts:

Gates for the timing belt kit: part number K015130XS
Valeo for the water pump: part number 506019

Ebay searches will be your friend, just be aware of sneaky listings that get returned because they list the parts as cross reference.
There's also one seller who'll advertise a valeo pump, then send you a message post purchase that they've just checked their stock and that's missing, so they're shipping you an alternative.

I covered the fitting here

Thanks Jeff.