Johnny G Pipe

Wouldn't it be nice to be able to afford a new Porsche?

So - needle went up, and never came down. Sill is stone cold. Must be my thermostat. Any other way to test it? Anything else likely to blame?

TIA, folks.

DarrylH

And miss all the fun?FWIW, when mine failed, they "tested" it by starting the car from cold, watching the temp rise, and feeling the oil lines to the front of the car. If it looks like a duck...

Rocket Rob

When mine failed, the oil cooler in the front right-hand fender well stayed cold as did the door sill. I hate to say it ..... but I am suspecting you have a failed thermostat too.

Johnny G Pipe

Good evening Canada and California! (EDIT - and New Hampshire!)

Details are: car driving fine today. Enjoying the country lanes, full of the joys. Stopped at nursery to pick up my daughter, and 10 minutes later saw the temp. needle at half way - sheesh, I thought, she must've cooled down enough to shut off the cooler while I was in getting Abbie. Then 5 minutes later, its up at 9 o'clock (why didn't they put @&*%$ numbers on these guages!?), then 10 o'clock, where it stopped, me driving with minimum revs at this stage..

I have a cooler fan over-ride switch, which immediately brings it down when I'm stuck in hot traffic - it made no difference at all. So the cooler's out of the circuit.

Now back home, the car's sulking in the garage, and all needles are back to zero.

I think these things are about 250 quid? Doesn't look too tricky to fit..

EDIT#2 - found some good stuff in the archives, like this:
https://rennlist.com/forums/showthre...ght=thermostat
As I'm pre-92, looks like I can't just change the element.

Johnny G Pipe

Sorry - good morning Hawaii!

See above edit..I guess the cooler would stay cold, as the cooler lines were cold when the engine temp was huge.

I have replaced both my oil tank and filter to thermostat line in the past few months, so I guess the thermostat is feeling left out!

C4porsche964

Symptoms sound the same as mine and yes, a new thermostat fixed it.

John Boggiano

You'll also notice your seatbelt gets very hot when you've left the car for a few minutes...

johnfm

John B

I don't think the seatbelt will get hot at all if the thermostat is buggered.

Senor G-Pipe - is the oil cooler cold when the temp gauge is @ 10.00?

JasonAndreas

If there is a circlip on the end of your thermostat housing than you can replace the insert (i thought the oil line locations changed from the previous model years but the internals were the same?) If you have trouble removing the cap put a drywall screw into it and pull with pliers.

dfinnegan

The markings on the temperature gauge are:

for the bottom two marks the bottom mark has no temp, but the upper of those two is 50 degrees C

The next mark (8 o'clock) is 90 degrees C

The next (10 o'clock) is 120 C

The top red mark (not sure top or bottom of the mark, but I think it's the top of the mark) is 150 C

So,

7 o'clock = 50C = 122F
8 o'clock = 90C = 194F
10 o'clock = 120C = 248F
Red = 150C = 302F

I've never been past 9 o'clock (even yesterday in mid 90's F stop-n-go traffic).

The information that I've found on this site indicates that getting above 9 o'clock is kind of rare except maybe at the track(?).

DarrylH

Given that you've done all that work in the neighbourhood lately, if you can get it open, it might be worth trying Indycam's suggestion of seeing if there's something jamming it up. Mine was knackered and replaced completely, but YMMV. If you do get the later one, the oil line locations are different as Jason says, so you may need a couple of hoses. Part number from invoice last summer is 964-207-047-08 OIL THERMOSTAT which was ~ CAD 550. Hoses were 964-207-251-03 and 964-207-241-06, another hundred or so. A few other odds and sods (clamps, clips, washers, etc) were also needed. Good luck.

drb007

I have a 90 C4 and I just replaced the element only. If was actually a very enjoyable job. I love working on the car!

Arrivare

When I had to have corrosion repaired on my thermostst last month I had to dismantle it. The dry wall screw to remove the cover did not work and I had to drill the cover out. I had a replacement cover made and everythimg went back together ok. The temperature is stamped on the element, mine was 80 deg C, and I tested it in hot water. You might be lucky and the element may be jammed in the closed position. I have attached a picture to show the bits that make up the thermostst assembly. I would try a repair before buying a new one .
Allen

Johnny G Pipe

Thanks chaps.

I do enjoy gradually expanding the boundaries of what I can fix on my car, but I'm just a little sick of the rear right wheelarch, having done lines, oiltank and brake discs and pads all in the last few weeks...

My part number is 964 207 407 03 , being a 90 MY. 08 is the '93 part, according to Adrian, maybe I would have trouble getting the earlier type.

I am going to take her out and have a look - I suspect the new(used) oil tank might have dropped a bit of crud in, right enough.

So, as ever, now I have the 101 on thermostats, and it seems that the element is only replaceable post 92, except for some exceptions..
-ahh, that hand-built fudge factor, don't you love it?-
..and I think I am an exception, as I have a circlip, yes?

This is getting exciting

Johnny G Pipe

Edit - thanks Allen. You seem pretty handy with this stuff. How did your rust repair go? I will be very pleased if I get my 'stat cleaned up enough to get permission to put it on a pink carpet!

BTW, the seatbelt gets hot cos of the oiltank, AFAIK - and it was still hot all around there, whereas averything aft of the thermostat was 'colder than a well-digger's ***'.

Could I ask also- is there a recommended tool to remove the circlip? I have needle nose pliers, (and some hammers..) Once that's off, I presume using a screw to remove the plate would leave a hole in it anyway, so I would need a new plate whatever.

I have a friendly local engineer shop, and I might take it to them.