Saabscene Saab Forum - Saab Technical Information Resource banner
1 - 15 of 15 Posts

·
Registered
Joined
·
50 Posts
Discussion Starter · #1 ·
I have a 2.3ECO auto, and yesterday I noticed something strange with the temperature guage...
Normally, the temperature guage sits exactly half way between hot and cold, but make it work and it shoots up to the red within 30 seconds

The oil level is on Max and the coolant level is half way between Max and Min when cold.

By make it work I mean fast acceleration or show it a hill, and there is an abundance of hills in this area.

So, can anyone tell me if this is normal, or a known problem or anything to put my mind at rest
 

·
Registered
Joined
·
1,245 Posts
No that is not normal. If you load the engine the temperature guage will rise a bit but not that much. Could be first signs of imminent head gasket failure, which is a common problem, or a partially blocked radiator matrix.
 

·
Registered
Joined
·
50 Posts
Discussion Starter · #3 ·
hmmmm..... sounds ominous.
and very expensive

I have read somewhere that the water system can have some problems/leaks. Perhaps draining and flushing the coolant system, and then some leak fix could help.
 

·
Registered
Joined
·
17 Posts
I had something similar with by 2.3T, shortly after washing it.
It turned out the connection to the water Temp sender (yellow wire) wasn't making proper contact. Wiggling it cured the problem.

Symptoms were guage shot up to red in a few seconds. I stopped (M25) checked coolant levels which were ok and no signs of any steam from water pipes.
Restarted engine and proceeded on my journey. Every time the temp guage when slighlt above normal, guage shoot up (i.e. slow moving traffic). Once moving again,
temp guage went back to normal. Got to work safely and coolant level was ok.

If your guage returns to normal again then you may have a similar problem.
 

·
Registered
Joined
·
50 Posts
Discussion Starter · #5 ·
thankyou, that sounds more acceptabe.

I have topped the fluid levels up to the Max marking, and it doesn't use any water, which suggests to me that it isn't the head gasket, touch wood

Where in the engine bay is the temperature sensor located???
 

·
Registered
Joined
·
17 Posts
The coolant temp transmitter is on the RHS on engine block (looking into engine bay from the front) on the thermostat housing. Its a Lucus connector (Yellow wire) attached to a brass disk thingy and the connector can be rotated quite easily.

Resistance reading should be:
20C 661-736R
80C 71.6-75.4R
90C 52.8-55.2R
100C 39.5-40.9R

Hope this helps.
 

·
Registered
Joined
·
661 Posts
Does your cooling fan cut in when the gauge reaches this dizzy height?, if not then i would suggest that the fault lies in the gauge or sender as mentioned previously as the cooling fan will start when the rad switch gets to a temperature way before the top of your temp. gauge.

Pete.
 

·
Registered
Joined
·
50 Posts
Discussion Starter · #8 ·
the cooling fan kicks in as expected.

After a run I had a quick look and noticed the top hose was really hot, but the bottom hose was only warm. Would a radiator cool the coolant that much, or does it suggest thermostat not opening, pump not working, or as suggested in the first reply, radiator core blockage
 

·
Registered
Joined
·
1,908 Posts
Top hose very hot, and especially if the water is boiling/bubbling, is a classic symptom of the head gasket leaking hot exhaust gases into the water jacket.
Garages can fit a pressure tester to the rad filler/expansion tank cap and check if cooling system holds it's pressure - to determine a leaking gasket.

I would check Temp sensor first, based on Geoff M's experience, and then remove and test thermostat using a basin of water and thermomitor to ensure water is at the correct 'opening' and 'closing' tempretures - to check correct function of thermostat.
 

·
Registered
Joined
·
50 Posts
Discussion Starter · #10 ·
If it is a leaking head gasket, would you expect the cooling system to become pressurised very quickly when running the engine from cold? It does appear to be under quite high pressure when hot. looks ominous
 

·
Registered
Joined
·
661 Posts
Get the car hot then place your hand on the lower half of the rad, if its cooler than the top it has a blockage-buy a new one if this is the case as flushing doesn't really work in my experience.

Pete.
 

·
Registered
Joined
·
1,664 Posts
If the thermostat is older than a year.replace it,but make sure you have a new rubber sealing ring,in three years I have had to change the stats in both 9k's at least twice,and if you should be tempted to remove the thermoswitch from the rad,be prepared to buy a new rad as the plastic cracks and nothing I have found will seal 'em.
 

·
Registered
Joined
·
1,908 Posts
If it is a leaking head gasket, would you expect the cooling system to become pressurised very quickly when running the engine from cold?[/b]
Yes, Lurky.

Exaust gas is more likely to leak with a blown head gasket on a cold engine than a hot engine. Because the block/head on a hot engine expands more than the head bolts, hence the head gasket is under greater compression when the engine is hot, than when it is cold.
NB: Some antifreeze additives change colour if exposed to exhaust gases. You could either get a garage to do the test or find some colour change antifreeze to test yourself.

If you need a new radiator, there are quite a few specialists who will rebuild one using the existing frame, which can be alot cheaper than a new unit. But bear in mind the plastic thermoswitch housing may reduce the life of a rebuilt unit, wrt Mike H's comment.
 

·
Registered
Joined
·
50 Posts
Discussion Starter · #14 ·
well, here's something new...
When the climate control is off, the compressor for the air con it still on!!
I have disconnected the wire feeding the pump and noticed the temperature problem still there, but less prominent, but fuel ecomomy has instantly gone from 24mpg to 30mpg.

I am still fitting a new thermostat to try and get rid of the engine temp problem.

Need to post a new question now
 

·
Registered
Joined
·
50 Posts
Discussion Starter · #15 ·
thankyou all for your help.
I have replaced the thermostat after testing it and finding that it didn't open in a pan of boiling water!!!
it now peforms correctly.

just the strange problem with the air con compressor.....
 
1 - 15 of 15 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top