Car question

[Richard Mason]

Problem with car......so ask on a dive forum, that makes sense.

I've just bought YAOS (yet another old Subaru), although this one is a 93 model, so better than the 83 model I gave away last year.

Anyway, had some welding done on the cat converter yesterday, picked herup from the garage last night.

On starting up, it took an awful long time for the temp gauge to start registering any sort of warming up in the motor, probably 5 or 6kms, which is much longer than my other one (89 model, now inherited by No 2 son) has ever taken. However, once warmed up, the needle sat about halfway up the gauge, compared with the normal 1/4 way up normal position.

Also, the electric radiator fan, which is thermostatically controlled came on and stayed on for the rest of the journey (15kms) shortly after, despite the fact that it's midwinter here, with air temp of around 5 degrees C that time of night, all the traffic lights were green and my speed didn't drop below 60km/hr for the whole journey.

I'm thinking that maybe the thermostat is a bit sticky, it's maybe stuck halfway open, meaning there's cold water circulating, thus explaining why it takes time to warm up but then it's getting a bit too warm once it's run for a while.

Any wise thoughts from the auto-mechanical experts on here? (apart from "stay away from 15 yr old cars")

[dry suit diver]

sounds about a right diagnosis. although i never heard of one sticking half way open.

[simon varley]

Rich, thermostat stuck part or fully open would explain the long time to warm up as more cold coolant is circulating, but not the fact that it runs hot - or rather that the gauge shows hot. With a working thermostat I'd be very surprised if it even opened given the driving style you explained and the weather we have.

'Stat change is easy (usually - don't know the details on a Subaru) Wouldn't even bother checking it given the price of a new one. Just do a swap.

It is possible that the high gauge reading is 'normal' for the car and your old model was reading low. There's quite a lot of variability in the sender and the gauge itself.

Might also be the coolant concentration. The difference between 30% and 50% is enough to make the car run a few degrees hotter/colder. The gauge is typically non-linear and you might get a large swing for only a couple of degrees.

Last thought is that it might not have bene degassed properly last time the cooling circuit was filled. If there's gas pooling in the head near the sensor that will give a bad reading. Get it warm and rev it up to 4000 or so for a few minutes. That should push any gas round and into the bottle

As long as the bottle is full and the gauge doen't rise above mid way, your not likely to be at risk of any damage. Just keep an eye on the bottle level to make sure it's not dropping

good luck