Ok heres my problem.....Last week the bearings on my water pump went out. So i changed the water pump and flushed the fluid. The guy who sold me the water pump said i should switch over to the orange coolant when i flushed it so i did. I filled the radiator, let run, let cool, repeat, repeat, repeat. the radiator and resevior are both full. My car is cooling fine, running at the same temp it did before, EXCEPT I now have a code 15, and i can not for the life of me figure out what the problem is. I have been told maybe there is air in the system and to bleed it out, but i can not find the bleeding screws i supposedly have. Do i have a bad sensor or something? The fan is also running constantly i assume because of this.....which is also very annoying. Please help find my problem before i bash the DIC to pieces with my fist until that stupid light goes out.

thanks

 

You should have 2 bleed screws. One on the thermostate housing and one at the base of the throttle body. They are brass screws.

 

I dont think his 89 had bleed screws. All I had to do on my 86 was to fill it up and start the engine up without the rad cap on. Once the thermostat opened, I manually rev'ed the engine to about 2-2.5k and began to fill the radiator until it was full. Then I capped the radiator and shut off the car to let it cool. Repeat and rinse . Dont forget to make sure the res tank is filled too.

 

:yesnod: Correct.. no bleed screws on an 89

 

I thought your code 15 problem was solved by plugging in the CTS?

Why you would put DexCool in an 89 is beyond me, but won't cause a code 15, and either will low coolant or air.

Just so you know, Chevy does not recommend using DexCool in pre 94 engines. There is a TSB on this issue - been posted several times.

 

i couldnt find it. i guess i need to look better because the plug i have unplugged is a two pronged one less than the size of a dime around. It seems to have another piece plugged on the end of it as well


[Modified by C4Fetish, 12:00 PM 4/30/2002]

 

what was the reason for not using dexcool in older cars? I have been running Dexcool in my 89 for 2 years no troubles.. I have a new motor though.

 

I don't fully know!

There was a guy from Dana that posted on the forum last year that they worked for quite a while on gasket and seal design and there were changes for DexCool.

DexCool also seems to be quite sensitive to air in the system.

There is a lot of conjecture I could offer, but won't as this topic tends to get folks worked up.

You could do a web search for the "problem" DexCool uses like the 95 Blazer and LT1 Impalla's, but alot of what you will find is moaning and crying and not a lot of reasons. If you really want fun, read about the Mustang guys that deceided to use DexCool and the insueing problems! :lol:

Personally, I don't see any advantage to DexCool in engines that did not come with it [cooling effectiveness the same, service life the same, silicates already in the system - so no water pump seal improvement] so I stick with green in engines that came green and orange with engines that came orange. Green is a know quantity in these applications, and I know how to deal with it; Orange is a different animal and I am not up-to-speed sufficiently, so I figure GM went through some pain to issue the TSB that does not recommend back service with DexCool.

BTW, on DexCool measure your pH once in a while and if it goes below 7.0 flush. Keep coolant levels topped and use a positive spring pressure vacuum release radiator cap [little dingle - dangle valve in center inside should have positive spring pressure].

 

That sounds about like the plug for the CTS. Probably a piece of the sensor in the end.

 

Is one wire black and the other yellow?

 

ok: i found the coolant temp sensor plug and it was already plugged in. Yes, one wire is yellow the other is brown. The wires were frayed so i cut out the frayed part and resautered the wire hoping that would be the fix to my problem, but it was not. Is there any way to test my sensor to see if its working properly>?? What else could my problem be?

thanks


[Modified by C4Fetish, 1:38 PM 4/30/2002]

 

You said the plug was loose and floating around connected to nothing, then you said the plug had something stuck in the end of it. Now you say it's plugged in but has a frayed wire that you soldered, and still get code 15?

OK, I'll bite. Disconnect plug from sensor and use a small piece of wire to short the plug together. Clear codes by removing negative battery terminal for 1 minute. Start car, you should set code 14. If still 15 the wires to that sensor are open, disconnected, broken at some point. This all in the code 15 post, you don't read these do you?


Are you pulling our leg?

Pete

 

okay........i confused myself and everyone here looks like... let me clarify

on the passenger side of the engine i have a plug it is two prong and round in shape, smaller than a dime in size....still to be decided what this goes to....also it has another plug looking thing on the end of it....

on the drivers side, i found the coolant temp sensor and yes, it was plugged in, but there was some tape wrapped around it and i pulled it off and the wires were frayed so i resuatered those

still a code 15 and thats where i am now

 

OK :lol: :lol:

The sensor that will cause a code 15 is in front of the engine. Remove intake tube between MAF and Throttle body. Look down below throttle body with flashlight, on front of the engine. That's the sensor you need to check. Try the code 14 test first, then we can check with an OHM meter if you have one.

I thought in the other thread you said you had a disconnected connector right above the water pump and below the throttle body on the front of the engine. That would cause a code 15! Stop looking at other sensors! :jester

 

will try the code 14 test as soon as i get home and post the results

 

just came back from outside......I reset the computer, unplugged and jumpered the terminals of the coolant temp sensor together, and still i got a code 15, not 14......so now what???

 

If you are on the coolant temp sensor in the front of the engine, below the throttle body:

First make sure you jumpered together the connector that goes to the sensor, not the sensor itself.

If that is the case then you have a broken circuit in the wire harness between the sensor and the ecm. You need to trace those wires back and try to find where there is a bad connection or broken wire.

To test which wire is bad:

You should have a yellow wire and a black wire. Jumper yellow wire to ground, code 14 should set (same proceedure as before). A similar test for the yellow wire is to use a DVM, there should be 5V between the yellow and ground (or between the yellow and black). If still code 15, test black wire with OHM meter to ground. Black wire should be near 0 ohms to ground, if open to ground trace black wire and find bad connection or break.

As you just did the water pump, it would seem reasonable to look around the work area, retrace steps.