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Guest Message by DevFuse

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95 legacy engine temp. gauge puzzle

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37 replies to this topic

#1 Guest_dtate_*

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Posted 17 December 2001 - 03:24 PM

Over this past weekend, my wife's 95 legacy wagon's(146K) engine temp. gauge started to rise and fall from it's normal operating range. Ever since we have owned the car, we bought it new, the gauge's indicator has remained in a position of about a 3rd of the way up the face of the gauge. Now, it has risen up to about 2/3 of the way up the face, and then it will drop back down. I checked the fans and coolant levels, both checked out OK. Today I took it to the local subaru dealer and had a serviceman checked it out. They pressure checked the system and everything checked out fine. They could find no problem with the cooling system. Any ideas????

#2 Guest_Legacy777_*

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Posted 17 December 2001 - 03:43 PM

Could be a messed up thermostat. You change it or do anything with it recently? Does it do it when you just started it up? Or after it's been warm for a while? You runnin heater, A/C, defrost?

Any more details would help.

#3 Guest_dtate_*

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Posted 17 December 2001 - 04:02 PM

New water pump was installed back in June, according to the records at the dealer, a new thermostat was installed at that time, so they discounted a faultly thermostat. The three times that the gauge spiked included running at highway speeds with the heater on, setting still at a stoplight, and once on a short drive, 7-8 miles. Everytime the engine has been running at the normal range before spiking upward. On the return trip from the dealer(25 miles, open road) I didn't see any problem.

#4 Guest_Frag_*

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Posted 17 December 2001 - 05:04 PM

If cooling system is fine, then maybe it's the coolant temp sender or gauge itself that's at fault.
Since the gauge sometimes indicates hotter than normal and since less ohms measured at the sensor connector register as hotter on the gauge, it's certainly not the connection that's at fault (that would give you more ohms and register as colder on the gauge). So that could mean thermistor element (in the sensor) malfunction or malfunction of the voltage regulator in the gauge itself. I think that rarely happens, but that's a possibility. Since you have to know the exact temp of the engine to effectively test the sensor's resistance range, i think this is not something you can test yourself. Or maybe someone more expert in that department can help you here.
Good luck.

#5 Guest_meep424_*

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Posted 17 December 2001 - 07:40 PM


I'm still thinking thermostat--- WHICH one did the dealer replace?

There is a coolant thermostat that allows the radiator to flow/not flow. There is, I believe (but could be wrong) a separate sensor for operating the fans. Either one of them could cause this problem.

('tis possible that the ECU temp sensor might drive the fans-- I dunno-- but I recall seeing 2 sensors on our 2.2L so I'm sort of doing this as an educated guess.)


#6 Guest_Legacy777_*

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Posted 17 December 2001 - 08:15 PM

In all honesty. For the price of a thermostat, I would get a new thermostat, a gallon of antifreeze, and spend an hour or so, flush the system with water, then replace with 50/50 mix. Make sure you get the OEM subaru thermostat.

#7 Guest_dtate_*

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Posted 17 December 2001 - 10:06 PM

I'm leaning toward replacing the thermosat myself. I will be driving the car tomorrow and will watch the gauge, but I am planning to go by the dealer and pick up an OEM subaru thermosat. I have replaced a thermosat on a 1990 Mazda B-2200 pick-up truck, but never on a sub. I understand it is located on the bottom of the engine, is this correct? I assume that it is situated where the lower radiator hose connect is. Any advice or tips that I need to be aware of ?

#8 Guest_Suzam_*

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Posted 18 December 2001 - 08:15 AM

How are the hoses? I have seen an older radiator hose "collapse" internally and cause partial blockage of the flow. The reinforced inner wall had peeled away from the outer shell and sort of flapped in on itself, restricting flow of the coolant. It caused similar symptoms in my '93 Mazda 626 with 146,000 on the clock.

#9 Guest_dtate_*

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Posted 18 December 2001 - 08:42 AM

Outside of hoses looks good, but that is something to consider.... Thanks for the info, and all of the posting.
I may go ahead and replace hoses as well as thermostat. Advice and pointers will be much apperciated!

#10 Guest_Legacy777_*

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Posted 18 December 2001 - 09:57 AM

Yes the thermostat is on the bottom where the lower radiator hose comes into the engine. There is a peakcock valve or whatever that damn thing is called on the passenger side of the radiator that you can use to drain the coolant. Then just loosen the two bolts holdin that little housing on for the thermostat. Then take your hoses off. It's not too hard a job. When you get everything replaced, fill the coolant system with just water and run it to help flush it out.

#11 Guest_dtate_*

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Posted 18 December 2001 - 10:34 AM

Thanks for the info Josh! Seems like it so be a simple enough job. I've been visiting the message board for about two months and this was my first posting. Have found the board and info on it very handy in understanding both of my subarus! Will let you know the outcome of this problem.

#12 Guest_Commuter_*

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Posted 18 December 2001 - 12:37 PM

I don't know if this applies to your car or not. I recently changed the thermostat on my 97 OB 2.5L and I noted that the thermostat is NOT symmetrical. It had to go in in a certain orientation. I've read elsewhere about this. If it is positioned wrong, the unit bumps up against part of the casing and won't open fully.

Again, I don't know if it applies to you, but just a word of caution.


#13 Guest_gbrand_*

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Posted 18 December 2001 - 01:18 PM

watch the cooling fans-may or may not be running when needed.

also, read old posts about "burping" air out of system.

For grins, when temp seems to rise, turn ON A/C and if cools, may be due to the fan that runs on the radiator when the A/C is on(my leagacy 91 has 2 fans, one to come on when temp gets hot and one to run when A/C is on). Also, trn on heater, is air normal hot or hotter than hell? may give you clue if temp gauge is reading properly.

#14 Guest_dtate_*

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Posted 18 December 2001 - 01:42 PM

I did check to see if both of the cooling fans were operating, and they were. Also, according to the local dealer's service dept., the system is operating fine, hopefully that includes the operation of the cooling fans.
Also, thanks for the heads up concerning the thermostat orientation, I will be sure to pay attention to that.

#15 Guest_Legacy777_*

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Posted 18 December 2001 - 02:14 PM

To my knowledge, both fans will kick on when temp gets too high. However when runnin A/C and temp is fine, I think the smaller one just stays on. But not sure about that.

#16 Guest_GBianchi_*

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Posted 18 December 2001 - 04:38 PM

you may have already, but if not check out the "cooling curiosity" posts on page 2. I'm still monitoring that situation and have not yet made a definite diagnosis.

#17 Guest_dtate_*

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Posted 18 December 2001 - 08:30 PM

O.K., the deed is done. I just finished replacing the thermostat, adding new coolant, and test driving the soob. So far....everything looks good, the temp. gauge is holding as it should, and no leaks!!!

Hopefully the drive to work tomorrow will be uneventful.

Thanks for all the info and interest, I will add a posting tomorrow night.


#18 Guest_Legacy777_*

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Posted 18 December 2001 - 08:59 PM

you do the burping ok? found the little screw on pass side of radiator?

#19 Guest_dtate_*

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Posted 18 December 2001 - 09:22 PM

I did find the screw located on the passenger side, follow the steps outlined in my owners manual, and was able to add as much fluid as I removed. After driving about 10 miles, was able to add maybe a cup or so more fluid.
So, hopefully I am ready to go.

#20 Guest_dtate_*

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Posted 19 December 2001 - 09:44 PM

Just thought I would follow-up with this posting. After changing out the thermostat, I drove the car about 65 miles today in varied situations(open road, in town, hilly terrain) and the gauge held it's position throughout the day. No spiking or any other unusual movement.

One thing about the thermostat that I removed from the car, it was nothing like the OEM stat that I purchased at the soob dealer. It was smaller and the base was round. Since this stat was the one installed by the dealer in June, it makes me wonder about if subaru has more than style of thermostats, or did the dealership install a non OEM stat in my car?? Anyway, the temp seems good now.

#21 Guest_Legacy777_*

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Posted 19 December 2001 - 09:59 PM

nope....the dealer farked up. They put an aftermarket thermostat in your car. There is only one type of thermostat, it's the same on my 90 as it probably is in the 2002 models.

I would personally go back and bitch at the dealer....but hey that's me ;)

If you don't see a fuji-heavy industries emblem it's not a subie OEM. It sorta looks like a crooked crescent moon.

#22 Guest_dtate_*

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Posted 19 December 2001 - 10:20 PM

I understand bitching to the dealer, but I don't think it would do much good. The issue with the temp. gauige is not the first incident of the dealer's service dept. and myself having differences about whether my car needs attention. About one month ago I had my 97 OBS (98K) in the shop to have them look into a knocking sound I was having in the front of the car while accelerating from a stop. The sound was(is)intermetate in nature and so the tech-person could not get it to occur. After inspecting everything connected to the drive train, brakes, etc., I was told that nothing was wrong with the car(sounds familiar). After looking through the archives on this site, I think I may have some issue occuring with a CV joint. All in all, I have had good results from the dealer's service dept., but I can't help to feel that I may be viewed as the customer that cries wolf.

Again thanks to all for the info, and I'm sure I will be using the site in the future.

#23 Guest_Frag_*

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Posted 20 December 2001 - 10:42 AM

Glad your problem is solved Ddate. Could you, just out of curiosity, put the old stat in a pot of water on the stove and check at what temp it opens. No obligation of course :)

#24 Guest_Legacy777_*

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Posted 20 December 2001 - 11:43 AM

It'll probably open on the right temp, the sizing and such for these subie thermostat's seem to be very critical.

#25 Guest_Frag_*

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Posted 20 December 2001 - 01:03 PM

The OLD, and presumably defective one 777.

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