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Discussion Starter · #1 ·
Follow the advice, follow the advice, follow the advice…..

Ah yes, kicked myself in the backside again. 1k miles ago when I bought the Saab, I had several error codes to fix and clear. One of the issues was the coolant sensor. As part of the repairs, I drained the coolant, checked the hoses, and changed the sensor. Though several knowledgeable people on this site recommended swapping out the thermostat while I was there, I didn’t see the point. It seemed to be working, I was not getting the classic Saab symptom of the gauge dropping to zero after around 15min of driving. So I left the old thermo in place.

Today my gauge dropped to zero at almost exactly 15 minutes of driving. Then my wife informs me that it happened to her also. I stopped the car, restarted, gauge came back, 15-20min later, gauge drops to zero again and I get the CEL. Just as described. The computer sees the engine temp not matching its model after 15 min or so of driving and kills the gauge as a signal. Happen X amount of times in Y amount of cycles and gives a CEL.

Guess what I’m doing tonight….

Oh and as a reminder to other new Saab owners, Follow the advice, follow the advice, follow the advice…..
 

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Sounds more like an electrical issue rather than a failing Thermostat. I would check and clean up the connectors to the temp sender.
It think the advice to change out the thermostat is good. For some reason they fail every 80-100k miles. Both of mine have failed stuck open. Car does not get to fully warmed up in cold weather.
 

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Discussion Starter · #3 · (Edited)
I have checked and wiggled the wiring when the gauge bottomed out and engine running and after restart with the gauge showing temp. No joy.

Several "saab guys" and one mechanic all described the same thing. If the gauge works fine, then goes to zero after 15 or so minutes, stop, restart. If the gauge comes right back as if nothing ever happened, it is part of the programing used as a warning that the engine is not maintaining a proper temp. The computer compares the engine temp to its model after running enough time. If this error happens enough times, a CEL will come on.

Their description matches what I am seeing. If the thermo swap fixes it, I will be a true believer. If not, then back to troubleshooting.

Rick
 

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I'm having the exact same issue. Just ordered the Coolant Temp Sensor today actually. Also today, I failed my emissions test because of the CEL caused by the sensor. I haven't even looked into the location of the sensor, was going to do that after I got the part. I gather this is a bad idea? I have 112k on the car right now and was going to do the thermostat when I did the timing belt/serp belt/pulleys/tensioners/water pump at 120k. Should I be replacing the thermostat when I do the sensor? ....and what all is involved with changing the sensor?

-Thank You
 

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Discussion Starter · #5 ·
Replacing the sensor was simple. Look in the stickys under minor maintenance. There is a walk through there. Same with the thermo.

Some swap these out without draining the coolant and only lose X-amount of coolant in the process. I would rather not have the mess and avoid having to rush something causing a problem like cross threading, etc. It's not as if coolant is expensive and it shouldn't hurt replacing it. (In my case it is a bit of a waste as I just replaced 1k ago. I will likely just lower the coolant level enough not to spill any in the engine bay)

Looking back, yes I would change out both if I was going to change out either. I didn't, as I had just spent hours on my back in a very cold garage dropping and cleaning the sump, oil change, new plugs, new DIC, coolant flush, and a new coolant sensor. I was standing there with everything complete except the thermo. I even had the new thermo in my hand! But I was cold, tired, and needed the car the next day. I skipped the thermo (as I considered it a preventative/ not needed repair), stuck the hoses back on, topped off the coolant, and called it a night. Another half hour in the cold might have prevented this issue. I'll find out soon.
Rick
 

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I have the v6, so I'm not sure how much worse/better yours is to replace. I found the Location of V6 Thermostat and fix in the 9-5 maintenance thread, but the screen grab says '98-'02 v6. I have an '03 and don't know if it's any different. I'm thinking not. Why change for just '03?
 

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Discussion Starter · #7 ·
Just looked at WIS for the V6 gas. Sensor should be as easy and appears to be near the same location. As for the thermo in the V6, I will leave that to someone who can help walk you through it. Lets just say that if I'm looking at this right, I've never seen a car that has you pulling the manifolds and MAF to change a thermostat. :eek:
 

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Just looked at WIS for the V6 gas. Sensor should be as easy and appears to be near the same location. As for the thermo in the V6, I will leave that to someone who can help walk you through it. Lets just say that if I'm looking at this right, I've never seen a car that has you pulling the manifolds and MAF to change a thermostat. :eek:
WHA?! uh uh. That's not how I see it. No offense, but I hope you're really wrong, lol.

http://www.saabcentral.com/forums/showthread.php?t=62421

I see them removing the thermostat housing, but not the Intake manifold or MAF.

Sorry to cut in on your thread, but since we're both having the same problem, maybe we can help the 4 and 6 owners at the same time.
 

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Discussion Starter · #9 ·
I hope I'm wrong too! I am looking at the 2003 V6 gas engine in WIS though. One thing that is great about this site is that knowledgeable people often give us an easier way than shown in the book!
 

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Fingers crossed, lol.
 

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Discussion Starter · #11 ·
OK, Thermo installed. Drained about a gallon of coolant and broke out the swivel sockets and extensions.

I'll touch base if this did not fix the problem, though it will likely take a week or so to find out.
Rick
 

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I had the same issue on my wifes '02 9-5, V6. I too replaced the temp sensor only to have the gauge drop to nothing after a little driving. It is the thermostat that fixed the problem. I dont know about the 4cyl but for the V6, you need to remove the upper intakes along with the MAF. This gives access to the thermostat and the metal pipe that it connects too. When removing the thermostat housing, you also need to remove one screw thats on the front of the forward cylinder head. This screw also holds the top of the engine oil dipstick in place...find the dipstick, its right behind it. Basically the metal coolant pipe is squeezed into the thermostat housing when you tighten this one bolt. There is no threads securing the two together, just two rubber O-rings which should be replaced. ALSO, be aware that many local autoparts store will sell you a cheap basic thermostat which wil not work. You need the actual Saab part that is the housing itself, which has the thermostat inside of it. I found one cheap on Ebay. Again this is only for the V6.

Aaron
 

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Discussion Starter · #13 ·
Yep, thats what WIS had.

Sorry Sparky, looks like replacing the thermo on the V6 is more involved than the half hour job I had on the 4. Good Luck
 

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Discussion Starter · #14 ·
Ok, It's been a hard driving week. Three, 40-mile round trips to work and a 900+ mile trip (14hrs) to go see our new nephew.

No gauge drop offs, no problems. Looks like the thermo was the issue even though it appeared to be close (just under) the 9-o'clock position prior to replacement.

If you are having the symptoms I had, go for the thermostat and swap that sensor while your at it!
 

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Well I'm glad everything turned out good on your end!

I picked up my coolant temp sensor Friday afternoon. Haven't installed it yet because we got snow and freezing rain here last night and it's gonna be too cold to do anything on the Saab today.

Your temp sensor/thermostat issue.... did your car quit blowing hot air? Mine still blows hot so I'm hoping I won't have to pull the intake manifold. I ordered the WIS cd for '98-'07 9-5's. So IF I have to pull the intake, I can cheat and use the manual, lol. I've never been hesitant to get in there and start tearing a car apart, until I got this car. Now, I don't wanna touch it unless I have an exact diagram showing what to do. Too afraid of it costing more money than it should I guess.

Wisneski, thank you for the guidance. It's always nice to have help from a "local". :D
 

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Discussion Starter · #16 ·
I had no problem with the heat blowing hot. The temp gauge was so close to the 9-o'clock position prior to replacing that I had discounted the need to replace the thermo. Live and learn.
 

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Wonderful, lol. I'll have my dad order the thermostat assembly on Monday. So I need the housing/thermo, 2 o-rings, what else? The intake manifold gaskets? Just ordered the WIS yesterday... maybe I should wait to order parts until I can see what all I'm gonna need. GRR. DIY sticky, here I come.
 

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I had no problem with the heat blowing hot. The temp gauge was so close to the 9-o'clock position prior to replacing that I had discounted the need to replace the thermo. Live and learn.

Yeah and there are still some deniers in this thread thinking its an electrical problem.. they too will live and learn lol
 

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Questions...

So this issue just started happening in my 2002 saab 2.3. with the 15 minutes drop to zero or not rise from cold at all. Should i just replace the thermostat, and see if that fixes it vs replaces sensor and stat at the same time? The other thing that has been happening leading up to this is the occassional Check coolant levels, which are never low. that has been going on for a little over a month. Today was the first time i got the CEL.
 

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So this issue just started happening in my 2002 saab 2.3. with the 15 minutes drop to zero or not rise from cold at all. Should i just replace the thermostat, and see if that fixes it vs replaces sensor and stat at the same time? The other thing that has been happening leading up to this is the occassional Check coolant levels, which are never low. that has been going on for a little over a month. Today was the first time i got the CEL.
When I had the issue, I replaced both and did a coolant flush at the same time. Just picked the car up a few months ago and figured that it wouldn't hurt to do a flush as well. ;ol;
 
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