Finally picked up my 96 SVX. Temp gauge moves around a little. - Page 6

Cam · #76 08-10-2010, 04:05 PM

Our radiators have been known to trap air when filled. If I remember correctly you should raise the front end of the car up with a jack and jack stands when you fill it, and then top it off once it is off the jacks. But that is my memory retelling something that svxfiles said a while back. Sound right Tom?

svxfiles · #77 08-10-2010, 05:10 PM

If the front end is elevated, either on jacks, or the steepest hill that you can find it does help to purge air from the system.
Filling it, and refilling it after it gets warm enough to open the thermostat also can help.
So, raise the front end,
fill,
run,
allow to cool,
top off.

However if its low on coolant in a week it could be a sigh of a bad headgasket.

Huskymaniac · #78 08-10-2010, 07:17 PM

Guys, a couple of questions.

What is the normal operating temperature range? Have any of you observed an accurate thermometer in the coolant path during a high stress drive?

What is the Subaru part number for the temperature sending unit? The part that came out of my SVX had the following stamped on it: 176-10-1Q-A where each number/letter combination is on one face of the hex "nut".

What is the resistance of the temperature sending unit at some standard temperature like, say, 100C?

Oh yeah, I noticed some really odd behavior on the way home today. When I accelerated the temp rose, which was expected, rapidly, which I did not expect. When I coasted the temp kinda just hung at wherever it was. When I hit the brakes, the temperature dropped pretty rapidly.

What can I do to get the air out if I don't have jacks or a nearby hill? Will topping off the radiator in the morning do it? What happens to the air as the engine temperature cycles up to operating temperature and back down to the outside temperature? Does it eventually work its way out through the overflow tank?

kwren · #79 08-10-2010, 07:35 PM

Quote:

Originally Posted by Huskymaniac

Oh yeah, how do I know if I had air trapped in the system? If I open the radiator cap after the engine cools and I don't see coolant, is that a sign?

it is definitely a sign.

I am keeping fingers crossed that it isn't a seeping head gasket.

However, keeping fingers crossed never works for me... sorry

Keith

kwren · #80 08-10-2010, 07:39 PM

Going in circles trying to find something that isn't is sort of like a dog chasing it's tail...

Again, I sure hope I am wrong!

Keith

svxfiles · #81 08-10-2010, 10:15 PM

Quote:

Originally Posted by Huskymaniac

1)What is the normal operating temperature range?
2)Have any of you observed an accurate thermometer in the coolant path during a high stress drive?

3)What is the Subaru part number for the temperature sending unit?
4) When I hit the brakes, the temperature dropped pretty rapidly.

1)210°f for the fans to come on.
Usually about 201°f when fully warmed.

2)Yes.

3)21203AA030

4)Bad ground?

Trevor · #82 08-10-2010, 11:56 PM

Quote:

Originally Posted by svxfiles

1)210°f for the fans to come on.
Usually about 201°f when fully warmed.

Huskymaniac, you could blank of the radiator to stop air passing, observe when the fans come and note the gauge reading. This should provide you with a means of checking accuracy of the simple good-bad calibration provided by the gauge.

kwren · #83 08-11-2010, 12:48 AM

The gauge is not going to cause the radiator to lose coolant...

Keith

Trevor · #84 08-11-2010, 01:38 AM

Quote:

Originally Posted by kwren

The gauge is not going to cause the radiator to lose coolant...

Keith

No one has suggested it would. When involved in a forum it is a prerequisite to read, assimilate and understand what is being discussed. Useless outbursts continue to annoy.

Huskymaniac · #85 08-11-2010, 06:41 AM

Well, I checked the radiator and overflow tank this morning and the radiator was full to the brim and the overflow tank was actually still above "H". I guess they put too much in yesterday when they tried to top it off after installing the new temp sender unit.

I let it run a while and it did go above the dead zone again. What is interesting is that it got close to the top white line but the fans never kicked on. When I turned on the heater, the fans both kicked on and the temp dropped fast. When I switched over to A/C, the fans stayed on and the temp rose again but slowly and not to as high as it got when I was idling with the climate control system completely off. So, I know the fans are working. I think I also know that the ECU did not think the engine temp got high enough to warrant kicking on the fans even though the gauge read almost all the way to the white line. I believe I read somewhere on this site that the fans kick on at 206F. So the ECU didn't think the temp got that high and I bet that temp should be within the "normal" range for which the gauge should be at its midpoint.

I tried the trick of letting the engine run with the radiator cap off to see if air worked its way out and the fluid level rose pretty quickly to the point of spilling over so I threw the cap back on. My driveway is pretty level and may actually be pointing slightly downhill.

Huskymaniac · #86 08-11-2010, 06:47 AM

Quote:

Originally Posted by Trevor

Huskymaniac, you could blank of the radiator to stop air passing, observe when the fans come and note the gauge reading. This should provide you with a means of checking accuracy of the simple good-bad calibration provided by the gauge.

That's well beyond my comfort zone with cars. They are getting a genuine subaru temp sender unit tomorrow so I will be putting that one in and hoping for the best.

Thanks to SVX files for the information on the fan temperature and part number. That matches up with other information I was able to dig up last night.

Sean486 · #87 08-11-2010, 06:53 AM

Quote:

Originally Posted by Huskymaniac

That's well beyond my comfort zone with cars. They are getting a genuine subaru temp sender unit tomorrow so I will be putting that one in and hoping for the best.

Thanks to SVX files for the information on the fan temperature and part number. That matches up with other information I was able to dig up last night.

Good luck with it Husky I hope that cures it.

Huskymaniac · #88 08-11-2010, 09:11 AM

Quote:

Originally Posted by svxfiles

4)Bad ground?

What I noticed this morning was that the fans both kicked on when I turned on the A/C while the car was idling. They were off when the A/C was off. Maybe the car automatically kicks on those fans when the brake is depressed, assuming that the car is coming to a stop, or maybe they kick on when the car drops below a certain speed. The temperature drops fast when those fans kick in.

kwren · #89 08-11-2010, 02:31 PM

Quote:

Originally Posted by Huskymaniac

Maybe the car automatically kicks on those fans when the brake is depressed, assuming that the car is coming to a stop, or maybe they kick on when the car drops below a certain speed.

Trevor, kindly refer to reply #12?

#12 is exceptionally nice!

(I call a spade a spade and a turd a turd)

A clue... no need to try to count them, Trevor, they are numbered.

Keith

The question mark after "Trevor, kindly refer to reply #12" has no meaning but was inserted because I never comply with people telling me what to do, especially when they cuss when doing it???

Huskymaniac · #90 08-11-2010, 04:47 PM

Quote:

Originally Posted by svxfiles

If the front end is elevated, either on jacks, or the steepest hill that you can find it does help to purge air from the system.
Filling it, and refilling it after it gets warm enough to open the thermostat also can help.
So, raise the front end,
fill,
run,
allow to cool,
top off.

However if its low on coolant in a week it could be a sigh of a bad headgasket.

When you fill and then run, how do you avoid the coolant from spilling all over the place as it expands? I didn't have the front end of my car raised today but as soon as the engine started to warm up, the coolant started to rise.