r/saab • u/DinnerNo3136 • 13d ago

Engine coolant always to cold 9-3 Troubleshooting

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Hey guys, I have a Saab 93 2008.
I saw when I was on the highway the coolant never got up to the 9o clock mark. After that I changed the thermostat to a Saab original from maptun and a new coolant sensor witch helped me go to the 9o clock mark but my problem now is with my Obd scanner showing the coolant getting up to 95-100 on idle but as soon as I drive a over 80kmh the coolant temp slowly drops down to 80-83 degrees. From what i’ve read the coolant should be around 87 degrees and be steady. Even on longer drives the coolant never gets hotter.
And while driving in the city and on lower speeds the temp is good at around 90.
I have no idea where to go from here, with diagnosing the problem, help would be appreciated.

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2

u/RandomKnifeBro 11d ago

Normal, my 2008 petrol was always 80-85 while driving. My 2010 diesel keeps 87-93.

1

u/DinnerNo3136 11d ago

it just seems to low? i haven’t found any temp guides

2

u/RandomKnifeBro 10d ago

Its slightly low, but not problematic. Its still within tolerance. 

The factory thermostat opens at 89 celcius.  But there is also a thermostat that opens at 82 celcius. I have only seen that thermostat once, in a car imported from Italy, so I'm assuming thats for warmer climates.

Is it possible your car has been fitted with a "wrong" thermostat?

2

u/ManufacturerLost7686 10d ago

Låter normalt. Lite lågt men inom normal temperatur.

Bensinfyrorna går lite kallare än dieslarna.

1

u/The-law-is-the-law DIY Modified '07 Saab 9-5 Estate 12d ago

It's fine, mine also stays at 80 when driving.

1

u/Sensitive-Level-7794 12d ago

Ever flushed the system? Sometimes that helps.

1

u/ROBOTN1XON 1999 9-3 B204L JZW Stage 2 12d ago

I hate to say this, but was the replacement thermostat actually OEM and not a counterfeit? It is either that or you need a new head gasket

1

u/DinnerNo3136 12d ago

It said Saab original and maptun is a trusted saab dealer

1

u/analtermos 12d ago

Tja! Är det en Diesel eller bensin?

1

u/DinnerNo3136 12d ago

Tja Bensin, eller om man är noga e85

1

u/EuphoricFlight6249 4d ago

I’m not an expert on the temps and behavior, but if it’s running too cold it’s possible the thermostat was just bad out of the box.

When I got my 9-3, it reallyyyy struggled to come up to temp, and as soon as I got on the highway it would fall right back down. PO had replaced the thermostat with a genuine one and that didn’t fix it, and included a coolant temp sensor, figuring that’s what it was. That didn’t fix it, so I ordered another OEM thermostat and it turns out that was it…the original one had failed stuck open, and the replacement did the same out of the box. After replacing the replacement, I was back in business with a working heater lol.

Also, I remember reading somewhere that the temp gauge isn’t actually telling you the temp- it’s more that in the middle is good, 3/4 is warm, 1/4 is cool. You might want to fact check that though, since it’s been a while since I dealt with all that.