Newbie 1988 928 S4

[Obby]

Hello, I recently bought an 88 S4 with 116k miles on her. The paint and interior were in great condition. The motor and tranny may need some work, small leaks.

I flushed the radiator due to an overheating that happened on a really hot day. Even after a full flush it will still almost overheat when driven hard (red light). Any ideas folks?

Ps. No leaks in the cooling system.

Thanks,

Obby (Steve)

Mods... Koni suspension, Borla full exhaust with headers. Not sure about the rest yet.

[928forlife]

Does the overheating happen when stuck in traffic or on the open road?

Could you go for a long hard drive on traffic free roads and still get over heating?

[Mrmerlin]

first things to do are figure out the history of the car.
Do you know when the thermostat was replaced??
Has the rear thermo seal been recently replaced?
How old is the water pump?
Are the coolant temp shutters still connected ( open them and pull the fuse)
Are both of your fans working?? do they seem to have a rising/lowering cycle to them ( do they both go faster or slower as the temps change?
Have you gotten an IR gun to verify the inlet temps?
Is the coolant bottle cap new?
What kind of coolant are you using?

Please answer these questions for a more precise diagnosis

[MPDano]

Do the S4's have a manual fan? If so, fan clutch?

[Danglerb]

Have you checked the flexplate and crank endplay?

S4 has dual electric fans.

Cooling system looks ok, overheats when run hard, YIPES head gaskets?

[Obby]

Originally Posted by Mrmerlin

first things to do are figure out the history of the car.
Do you know when the thermostat was replaced?? How can I tell?
Has the rear thermo seal been recently replaced? How can I tell?
How old is the water pump? Again, how can I tell?
Are the coolant temp shutters still connected (open them and pull the fuse). They are closed. How do I open them and where is the fuse for them. I still don't have a manual for the car yet.
Are both of your fans working?? do they seem to have a rising/lowering cycle to them ( do they both go faster or slower as the temps change? The fans are spinning (not sure about speed changes).
Have you gotten an IR gun to verify the inlet temps? Nope.
Is the coolant bottle cap new? No.
What kind of coolant are you using? I had the coolant flushed and topped with whatever Speedy Service Center uses. Looks green and clean.

Please answer these questions for a more precise diagnosis

All good questions, unfortunately I cannot get the history of the car. I purchased off an older gentleman that only owned it for a year or so.

My answers are above...

Thanks!

[Obby]

Originally Posted by 928forlife

Does the overheating happen when stuck in traffic or on the open road?

Could you go for a long hard drive on traffic free roads and still get over heating?

Definitely in stop and go on the freeway. When I get it rolling at about 70 mph it seems fine, a little on the high side. Also, when I WOT it for a while, it will get up there fast.

[Rixter]

if you have no service history on the car I would do a timing belt/water pump job asap, also change the t-stat

[Mrmerlin]

Since you have no service history go to www.928gt.com find page 2 then the links then print off a fuse/relay chart. for the car.
Then open the hood, see if the flaps are closed,
if they are start the car and see if they open.
if they stay closed turn on the AC system, are they still closed?
If they open then pull the fuse for the cooling flaps.
If they stay closed then shut off the engine, go to the front of the car lean over a bit and just behind the flaps in the center, is a round thing with a rubber cover, this is the flap motor, pull the cover off and then spin the knob till the flaps open. spray some silicone or WD 40 into the rubber cover so it slides back in place.
Since you have no service history I would either take things apart and inspect them or take the car and have it done.
You need to know the condition of the timing belt. If there is any doubt then have it replaced, if the water pump checks good then leave it alone.
You also need to check the flex plate
the condition of the car in general, any leaks, oil pan, steering rack, trans.

If opening the flaps lets the car run cool again then you might be OK.
But you should atleast consider removing the thermostat and replacing it as well as the rubber seal behind it and the coolant bottle cap. These are the least expensive things you can do to insure continued service

[Obby]

Originally Posted by Mrmerlin

Since you have no service history go to www.928gt.com find page 2 then the links then print off a fuse/relay chart. for the car.
Then open the hood, see if the flaps are closed,
if they are start the car and see if they open.
if they stay closed turn on the AC system, are they still closed?
If they open then pull the fuse for the cooling flaps.
If they stay closed then shut off the engine, go to the front of the car lean over a bit and just behind the flaps in the center, is a round thing with a rubber cover, this is the flap motor, pull the cover off and then spin the knob till the flaps open. spray some silicone or WD 40 into the rubber cover so it slides back in place.
Since you have no service history I would either take things apart and inspect them or take the car and have it done.
You need to know the condition of the timing belt. If there is any doubt then have it replaced, if the water pump checks good then leave it alone.
You also need to check the flex plate
the condition of the car in general, any leaks, oil pan, steering rack, trans.

If opening the flaps lets the car run cool again then you might be OK.
But you should atleast consider removing the thermostat and replacing it as well as the rubber seal behind it and the coolant bottle cap. These are the least expensive things you can do to insure continued service

Ok, the cooling flaps were closed. I idled the engine untill the fans came on. The flaps open just a bit around that time. I decided to do what you said and pull the 7.5 amp fuse and turn that middle knob on the flap motor to open them all the way (btw- i never seen such a huge fuse panel my whole life ). It's seems to run cooler now, around the middle of the gauge.

Leaks.

1. Yes, I have a tranny pan leak. I finally found the filler, geez they hid that well, right-side of the tranny? What the heck! Anyways, I topped it off a couple weeks ago when I bought it. Still leaking slowly though.

2. Something leaking red fluid (looks like tranny fluid) under the engine pan on the right front side of the engine. Can't really see to sell where it's comming from. But it's pretty wet under there.

Good news, I do not see any engine oil leaks and the timing belt look to be in good condition.

I'm thinking about bringing it to a shop for a checkup just to be safe. Is any foreign auto shop ok or should it be the dealership only?

Thanks again for you help. Keep it coming.

[MPDano]

Red Fluid from the front of engine sounds like Power Steering. Open your PS Reservoir and make sure you have enough fluid in there. Probably will need to do some cleaning up in that area to figure out the source of your leak.

[Mrmerlin]

if you see fluid leaking red on the right side of the car you should slide under the car and determine if its from up front on the right or closer to the cats on the right.
Some of these lines will begin to leak , there are trans fluid lines on the right side of the radiator and these can sometimes be fixed by cutting off the factory swages and replacing the fluid line with new hydraulic lines.
If the lines over the cats are leaking . dont start the engine till this is fixed otherwise the car will catch on fire and burn to the ground

[MPDano]

Originally Posted by Mrmerlin

if you see fluid leaking red on the right side of the car you should slide under the car and determine if its from up front on the right or closer to the cats on the right.
Some of these lines will begin to leak , there are trans fluid lines on the right side of the radiator and these can sometimes be fixed by cutting off the factory swages and replacing the fluid line with new hydraulic lines.
If the lines over the cats are leaking . dont start the engine till this is fixed otherwise the car will catch on fire and burn to the ground

That's right! Trans Fluid lines going to one of the Radiator Coolers. My Auto has 2, one for the Engine Oil and one for the Trans Fluid. Got my left and rights switched around.

[Danglerb]

You need to find a mechanic experienced in the 928, a dealership or general foreign car or even a Porsche specialist should never touch your car.

Hook up with the NorCal 928 owners group, and talk to Bill Ball about checking the car over, which is a great idea and highly recommend prior to purchase.
http://norcal928.org/

[morriss]

The pwr steering takes trans. fluid. If it's leaking red near the right front wheel then there's a good chance the steering rack lines or seals are leaking.