'99 Coolant over flow tank vent line help ? ?

[HikinFool]

Just picked up Saturn from shop. They diagnosed it as having a "fan driver blown temp sensor grounded." They said that the fan is not operating as it should due to the "computer" being bad. My fan does, in fact come on, but only when it gets really hot (almost to red on gauge). They wanted $275 to rebuild computer...
What computer would this be, can it be found used? is it something that can be easily replaced if I find one? I should also mention that I DID hook up my scanner to system and got ZERO codes, however, the "service" light is on...I am due for an oil change...I know...
Thanks all for the help...again!

[Waiex191]

Originally Posted by HikinFool

What computer would this be, can it be found used? is it something that can be easily replaced if I find one?

That would be this one here:


The box with the 1 and bar code sticker. Easy enough to pull from the junkyard.

[HikinFool]

@Waiex191, just saw your response...thank you!
Is that the front of the vehicle that I am seeing? Also, I'm heading out to junkyard right now to get one...hopefully. What tools would I need, and is that picture of a 1997, or does it matter? And, can you share the name of that part? And are they VIN specific? Sorry, I'm rattling off a bunch of questions, but I need to get this thing road worthy this weekend.

[Waiex191]

The picture is through the windshield. You have to pop off the dash cover. I've never removed it so I don't know what tools you need. I'd look for a similar year/optioned Saturn. That means Gen 2, 96-98 and same style transmission, same number of cams. Others here know the compatibility better than I.

[billr]

I gotta say... something seems screwy to me. If the CEL is on, I think there must be codes. Are you relying on that one shop for a diagnosis, or have you had it scanned for codes in other ways. That is a pretty specific diag, they gave, any clue how they came to that conclusion? Didn't you say that you have read actual coolant temp, and it is not really getting too hot?

Has the ECT sensor been checked/changed?

[fetchitfido]

If CEL is on, any OBD-II code reader can read the codes.
If the Service (Wrench) light is on it requires a more advanced code reader, usually of the Tech-2 variety. Generally the Service light is to indicate an "idiot" bulb issue in the cluster.

The radiator fan isn't supposed to turn on until 222f, where that is on the gauge varies a LOT by generation and a bit from car to car within a generation. '96-'99 (2nd gen) is between 3/4 and the red marks, '91-'95 (1st gen) is at the red marks and '00-'02 (3rd gen) is between 1/2 and 3/4.

One of the pictured modules is the PCM, the other is the ABS controller. The PCM should be marked with something along the lines of "perf" for DOHC's and "auto" for automatic. The ABS controller should be marked as such as well. Both are secured in place with 10mm nuts, the dash cover has 2 7mm bolts under plugs in the middle that face the wrong way to be seen from the seats.

[TomM96]

If that 'deaeration/bleeder' hose was clogged... that would explain the
surging, etc.

You state that the new hose flows constantly while engine runs... that is proper & necessary.

I hope you flushed the cooling jacket a couple times when servicing the antifreeze/thermostat...

If the coolant mix is about 50-50 (50%) antifreeze(green) and water
(purified-- R-O, distilled, or deionized)... the system pressure will be less than 15psi, more like 2psi. Soo good antifreeze mixture Saves Seals @ water pump,
and radiator, and heater core.

The proper coolant level in expansion reservoir is about 1/4" Below the seam
- At or above the seam will create excessive pressure in system.
.................................................. ..................

I would go slow on PCM. Need same car with same trans/engine/abs/etc; may require dealer program.