how far up should temp indicator go?

[rammstein]

As long as my car is moving the needle never strays above the lower 1/3 hashmark (lower white line). But to my surprise, while sitting in traffic in the rain at 40 degrees F, the needle rose all the way up to the upper white line. Even turning the heat on didn't seem to help much. Is this ok or bad? I wouldn't want to find out when I get stuck in traffic and its 80 out. Coolant level is fine.

Also, my car came with no hood insulation. Is there a good reason to replace it?

[rob83944]

Check the radiator fans to insure that they are going on. Start the car and watch the temp guage. If it keeps going up and the fans have not turned on, it's the fans.

BE CAREFUL NOT TO OVERHEAT THE ENGINE, AS THIS WILL BLOW THE HEAD GASKET. A MUCH GREATER AMOUNT OF TIME AND MONEY TO FIX

I suspect that while driving the air flowing over and through the radiator is keeping the coolant cool enough to keep the temp gauge in the 1/3 to 1/2 temp setting.

If the fans are not working, it is most likely the temp control switch located on the right hand of the radiator, looking at the front of the car. This is not a difficult part to change, just awkward in it’s position. Stand over the radiator and look down and to the right. You will see the switch half way down the radiator between the radiator and the engine, under the fan housing.

You need to remove the fan housing to get to the switch. Four screws removes the fan housing, then you can remove the switch after draining the radiator. (VERY IMPORTANT).

BE CAREFUL NOT TO STRIP THE RADIATOR WHILE REPLACING THE SWITCH. THE RADIATOR IS PLASTIC AND SEVERAL HUNDRED US DOLLARS TO REPLACE. A think a 24MM socket fits, but not sure.

The switch costs 20-25 dollars, make sure you get the switch for your years model. The early years switch will not fit later years. Pelican has the part. Also get the 50 cent washer. Takes about 1 hour for the job.

I think Pelican has a procedure for testing the fans by running wires from the battery to the fans. BE CAREFUL NOT TO CHOP OFF YOUR FINGERS. DO THIS TEST WITH THE FANS OUT OF THE CAR, SO THAT WHEN YOU JUMP WHEN THE FANS START, YOUR FINGERS ARE NOT IN THE WAY - THIS IS A VERY MESSY MESS TO CLEAN UP, PLUS IT WILL WRECK YOU DAY.

[Z-man]

The later cars (like my '89 S2) did not come with hood insulation. There is no real need for it, IMHO.

Pressure test your system to ensure you have no leaks.

Also: you can replace check the thermostat to see if it is functioning properly.

When was the last time you flushed the coolant system? If it has been more than 4 years, it's time for a flush!

Also: your H2O pump could be on it's way out. The pump is kinda hard to inspect without removing it, but if your fans are working, and your thermostat is ok, and your coolant has been recently flushed, and you have no leaks, it could be your H2O pump.

-Z-man.

[andrewgoh]

My water pump and timing belt was changed about 6 months ago (at the time when I purchased my 944). It would run between the 1/2 and 3/4 mark.

* The fan would cycle-on when the temp reaches the 3/4 mark. So, this tells me that the fan sensor is working.

* I checked the coolant level (cold engine) a month after the water pump was installed. The coolant level was slightly below the "minimum" level. I topped her up (below the maximum level). Now....4 months later....I see that the coolant level is back slightly below minimum.

* I checked compression...around the 180s to 195s....so don't think that there is a leak in the head gasket

* Checked engine visually....no leaks of coolant whatsoever on the block or shopfloor.

Should be concerned about the temp always being around the 1/2 to 3/4 mark?

[Scott R]

Sounds like an air pocket somewhere. Like Zoltan suggested get a flush and fill, then bleed it well using a pressure tester if you have access to one.

[andrewgoh]

Thanks for the advice.

I did recall this...I called the shop a few weeks after the installed the new water pump (a few months ago)...and expressed my concern. They indicated that this is normal...something about different thermostats being used (?). At the time, I was new to the P-car, and I was not in a position to validate the comment.

I'll take it back to the shop for a flush, and will let y'all know in a few weeks if there is a change (hopefully, for the better)....

[carolinus]

When I replaced my thermostat, it did the same thing. The fans should come on, though.

[rammstein]

Well, I took it out for a drive and then let it idle about 2 minutes, the needle was between 1/2 and 2/3, where supposedly the fans would come on and no fans (I assume the two fans right behind the radiator). I let it get a little hotter and still nothing. I've never overheated, probably because its been so cold this winter. So as far as me taking it out (the fan mechanism) it looks a little too tedious for me, especially since I don't really have a garage or much experience. It certainly seems like it would take more than 4 screws to get it out. Any idea what this could cost to have a mech help out?

[green944]

I noticed that my fans come on just before reaching the max mark. My car has never overheated but that seems awful high.
Any thoughts?

PS.. sorry not trying to jack the thread

[Britwrench]

I've never bothered or seen the need for flushing the cooling system.
Unless the oil cooler seals have let go there shouldn't be anything to flush. Probably the fan switch has failed.

[rammstein]

Well, I took it out for a drive and then let it idle about 2 minutes, the needle was between 1/2 and 2/3, where supposedly the fans would come on and no fans (I assume the two fans right behind the radiator). I let it get a little hotter and still nothing. I've never overheated, probably because its been so cold this winter. So as far as me taking it out (the fan mechanism) it looks a little too tedious for me, especially since I don't really have a garage or much experience. It certainly seems like it would take more than 4 screws to get it out. Any idea what this could cost to have a mech help out?

[newoldguy]

I might have gotton lost in the threads---but did any body suggest turning on the air conditioner? As I understand it, if you turn on the a/c the radiator fans should turn on. This way you'll know if they at least work in that condition.

Also, and I can't remember who posted this first, but another friend posted a chart showing that the temperatures corresponding to the marks on the gauge (late 944) are as follows: Bottom of the fat mark = 40 degrees C, top of fat mark = 60 degrees C, first skinny mark is 80 degrees C, second skinny mark is 100 degrees C, and the bottom of the top "right arrow" is 115 degrees C.

When I replaced a thermostat last fall, I was stumped because my car would run near the second skinny mark and I just knew it was too hot. After multiple attempts to figure this out, I narrowed it down to a bad brand new thermostat, replaced with another one and now it runs steady just below the 80 degree mark!

[Lawrence Coppari]

There is a temperature switch plug-type thing on the driver's side of the radiator facing the driver. It has two leads on it. With the engine off, pull the leads off and connect one to the other by a wire or nail or something of that sort. Now start the engine. The fans should run. If they do not, it could be a relay or bad fans. I'll bet it is either this switch or the relay. I have a 1986, 951 also.
I would do this test before replacing the switch.

If you have to replace the switch, don't over tighten and ruin your radiator. This gets done upon occasion.

[todwic]

Originally posted by newoldguy
I might have gotton lost in the threads---but did any body suggest turning on the air conditioner? As I understand it, if you turn on the a/c the radiator fans should turn on. This way you'll know if they at least work in that condition.

That's what I was gonna say. My stock fan switch made the fans come on about the $frac12 way mark, and I had it replaced with the lower temp switch. Now it comes on a little sooner, midway bewtweein the first and second mark.