temp gauge ?

Barr

Hi all

I went to test drive a 1994 BMW 316 tonight from a private seller. Something I noticed is the temperature gauge did not work on the car.
Would this be a relatively cheap thing to fix or could it indicate a bigger problem?

Also the heater would not blow hot air only cold -could this be related ?

Thanks in advance

Sonnenblumen

Might be as simple as the need to replace a faulty fuse, but get it checked out because Beemers Coolant systems can be expensive to repair. I had a problem with a 520 some years ago. It cost me a lot of time in/out garage and expense. In the end the whole thing had to be replaced ie new rad, cooling pipe, coolant bottle etc. Even thinking about it now makes me annoyed, have stayed away from Beemers ever since.

BMW - The drivers ultimate pain in the hole(and pocket) when things go wrong!!

damo605

Well if the heater wouldn't blow hot air then maybe the temp guage is working and the car just isn't heating up?
Not sure if the 316 has an electric fan or engine driven fan like the 6cyl but if engine driven maybe the fan clutch has failed and is over-cooling.... If electric, maybe it has been wired to stay on continous to mask an overheating problem the car has?
Either way I would run for the hills - There are plenty of those cars for sale out there so go buy a working one

Lex Luthor

damo605 wrote:

Either way I would run for the hills - There are plenty of those cars for sale out there so go buy a working one

Yip...I agree...run forrest run.

Dilbert75

Could also be that the thermostat is stuck open - that'd possibly do it. How much driving, and what type (slow town / high speed open road) did you do? Was it long enough to normally get it up to speed?

Was there coolant in it? If there wasn't, its likely the temperature sender unit has no liquid from which it can sense temperature - also there's nothing to transfer heat to the heater matrix.

cantdecide

i'd be very suspicious. clever people often "modify" their thermostats to stay open to keep the engine cool when they start overheating. aren't bmws notorious for head gaskets??

AMurphy

Even with the thermostat removed the water still gets hot, so the cabin heater would at least be warm, if not hot.

Anything is possible, but if you are in the mood, check the pipes to the interior heater matrix are not cut and looped around, so no water ever flows through it now, it could hve spring a leak in teh past and rather than fix it, the "loop back" is a perfect solution.

Alternatively, it could be a simple valve, either water, or an air flap in the air directional controls. And if these flaps are motor driven, could be the motor(s).

The temp gauge should register some change in temp, even if the thermostat is missing. May be the sensor, or the dash or wiring. Disconnect the wires from any or all temp sensors on the engine and see if it responds.

Barr

[PHP]Could also be that the thermostat is stuck open - that'd possibly do it. How much driving, and what type (slow town / high speed open road) did you do? Was it long enough to normally get it up to speed?
[/PHP]
I drove the car in city conditions for up to 20mins , this should have been plenty time for the engine to heat.
[PHP]Was there coolant in it?[/PHP]

checked this as well and it seemed to be fine , not oily either so thought head gasket should be ok

[PHP]Even with the thermostat removed the water still gets hot, so the cabin heater would at least be warm, if not hot.[/PHP]
It was blowing out very luke warm air at best and this was at maximum heat settings

The guy selling the car is looking for 2k. It seems cheap enough even if I have to fix something major in the engine.

AMurphy

[QUOTE=Barr......
[PHP]Even with the thermostat removed the water still gets hot, so the cabin heater would at least be warm, if not hot.[/PHP]
It was blowing out very luke warm air at best and this was at maximum heat settings

The guy selling the car is looking for 2k. It seems cheap enough even if I have to fix something major in the engine.[/QUOTE]

Maybe, IF you are doing the repairs yourself and Know in advance what is required.
I left a BMW pards Dept $400 short and carying the equivalent of a plastic shopping bag of parts... more expensive than gold and that was US prices, so BEWARE.
So how skilled are you?.
Do you have a real manual for debugging.
and
Do you have the time/garage.

Last time I looked at a BMW it had more "thermo-sensors" sticking out of the water jacket than a Porqupine has quills, at approx $150 each, you'd better be sure.

So if we can determine it does not have a blown head gasket, AND within your skill lever, it MAY be worth the effort.

Blown head gasket typ observations;
Coolant loss.
Overheating suddenly after a hot run (and coolant loss)
Overheating while the gauge registers cold (due to gas bubbles).
Oil in the water, water in the oil, Gunk on the dipstick and oil filler cap.
Steam in the exhaust, continuous and excessive.
Fouled or very clean plugs. (generally very different plug coatings).

Other items which cause overheating and not a blown gasket;
wrong diameter/rotation, free, broken pump impeller.
Wrong/small pump pully
plugged radiator, either not flowing air or water per spec.
Thermostats
Fan clutches
Air leaks


If electric fan(s),
Failed switches, motors, wiring, wrong rotation,
Failed AirCon controls

OTOH, it occurs to me that this is a 16, small engine, heavy car.... a "18" might be better value that age. What mileage on this item?.

Good luck.:)

Barr

Maybe, IF you are doing the repairs yourself and Know in advance what is required.
I left a BMW pards Dept $400 short and carying the equivalent of a plastic shopping bag of parts... more expensive than gold and that was US prices, so BEWARE.
So how skilled are you?.
Do you have a real manual for debugging.
and
Do you have the time/garage.

Last time I looked at a BMW it had more "thermo-sensors" sticking out of the water jacket than a Porqupine has quills, at approx $150 each, you'd better be sure.

So if we can determine it does not have a blown head gasket, AND within your skill lever, it MAY be worth the effort.

Blown head gasket typ observations;
Coolant loss.
Overheating suddenly after a hot run (and coolant loss)
Overheating while the gauge registers cold (due to gas bubbles).
Oil in the water, water in the oil, Gunk on the dipstick and oil filler cap.
Steam in the exhaust, continuous and excessive.
Fouled or very clean plugs. (generally very different plug coatings).

Other items which cause overheating and not a blown gasket;
wrong diameter/rotation, free, broken pump impeller.
Wrong/small pump pully
plugged radiator, either not flowing air or water per spec.
Thermostats
Fan clutches
Air leaks

Thanks for the advice ...... very usefull stuff indeed

Was going for another look tonight but the car was sold !! You snooze you loose I guess. Have to wait for another one to come up

OTOH, it occurs to me that this is a 16, small engine, heavy car.... a "18" might be better value that age. What mileage on this item?.

This was just to be a second car a city run around .. started off looking for a Ibiza 1.0 lol , i was trying to keep the tax and insurance down

oh and the BMW had 113k on the clock