Another guy with cooling problems!!!

[95rsdinker]

Sorry for the similar post but I am tired of researching and just need to ask. Ugh! SO I have replaced everything! Radiator, thermostat (twice), coolant temp sensor, radiator cap, water pump, head gasket and of course coolant. And it still over heats. I have found that my fans have a mind of their own and come on intermittently...even when I have the A/C on. So I get that this is a problem. But, despite that issue I took it out for a test drive after my water pump install tonight and it over heated again after 7 minutes, at 40mph, in 37 degrees. ???

I obviously need to fix the fans. Is this done by replacing the ECU? I was told the ECU was new when I got the car 1 onth ago. The fuses and relays are good. I don't really want the fans to be running all of the time, so I am trying to stray away from direct wiring them to an accessory power source.

Anyways, it seems to me that the fans are the only thing left in the cooling system to check. Right?

Why would she overheat in such cool weather despite the fan issue?

Idea...I haven't replaced the sensor that tells the in dash gauge what the engine temp is. Could this be giving me false readings? It appears to be working fine. Just thinking.

Anyways, any help would be much appreciated. I am expecting a baby any day now and I would like to get this problem taken care of before the little one comes.

 

[drewvr4]

Alright here is what you need to do, since you replaced everything I highly doubt your overheating. Get yourself a datalogger or go to a local shop that can do live diagnostic.

Plug it up to it and run the car, you have a Coolant Temp Sensor that the ECU reads but does not put out the reading on your dash, that has a seperate sensor which sounds like you replaced. See what the other sensor is reading first before going any further

 

[Blitzeclips]

Alright here is what you need to do, since you replaced everything I highly doubt your overheating. Get yourself a datalogger or go to a local shop that can do live diagnostic.

Plug it up to it and run the car, you have a Coolant Temp Sensor that the ECU reads but does not put out the reading on your dash, that has a seperate sensor which sounds like you replaced. See what the other sensor is reading first before going any further

Come one dude this is 420a section we don't have DSMlink. Better yet why the hell would you go buy a datalogger for this you could go to pepboys and have them check a code for you if it's coming from the ECU.

The fans do NOT need to be raplced with an ECU. You can go out and buy fans seldomly and solder then up to the existing OEM fan harness. Worked fine for me I've had zero problem in over a year..

It's either that or your coolant temp sensor is giving a false readout. EVen then I'd grab a multimeter and check for voltage consistencies before I replaced the sensor..

Good luck with it man. Come back and let us know what happens. Congrats on the baby too!!!

 

[drewvr4]

Come one dude this is 420a section we don't have DSMlink. Better yet why the hell would you go buy a datalogger for this you could go to pepboys and have them check a code for you if it's coming from the ECU.

Well I don't know what you guys use it was a suggestion so was the datalogger, but also notice afterwards I said take it to a shop to read what it was...calm down paco

 

[Blitzeclips]

Well I don't know what you guys use it was a suggestion so was the datalogger, but also notice afterwards I said take it to a shop to read what it was...calm down paco

paco. Haven't heard that one in a min. No your suggestions were good and correct I was just reminding you we can't use DSMlink.

 

[XMasta19]

You're both n3wbs hahaha...voltage consistencies? What exactly does that mean?

If you wanna verify that you're overheating. Let the car warm up to the point that it begins to go towards the hot side. You pop the hood...you check that the coolant fans are on, check to see if you're really even overheating...is the coolant bubbling, boiling over etc? First step in diagnosis is to simply verify the complaint...let us know what's up, good luck

 

[Blitzeclips]

You're both n3wbs hahaha...voltage consistencies? What exactly does that mean?

Actually and obviously you're the newb.

It's checking the voltage output of a possibly faulty sensor. You know what consistency means? You know what voltage means? It meens if the voltage isn't consistent, that's probably the problem. Let's say a sensor runs on 12V, yet when you check it using a multimeter it's reading 10.3-11.7 voltage output, that means the readings ARE NOT consistent, as it is showing a drop and/or raise in voltage output. In turn, meaning the sensor isn't recieving sufficient voltage to operate properly, accurately, and correctly.

Or you can just look it up.

 

[absolute_DSM]

With all that overheating youve been doing, Im surprised youre not eating coolant with a warped head. Better you didnt check that when you threw a new head gasket on?

 

[VelocitàPaola]

Huh?

Different sensors send information in different ways. The camshaft position sensor, crank angle sensor, vehicle speed sensor, etc. send 5V pulses - the information is encoded in the time on or off. The throttle position sensor, coolant temperature sensor and intake air temperature sensor send a variable voltage level based on changing resistance.

While you could measure the voltage going to these sensors, that will not match the voltage coming from them. The best way to check temperature sensors is to subject them to different known temperature points, then measure their resistance with an ohmmeter. There is documentation floating around which demonstrates which temperatures correlate to which resistances.

Then again, such an exhaustive analysis of the sensors is probably overkill as they're cheap and easy to replace.

Tom, I'm not sure what you're talking about exactly. Checking for continuity (kind of like 'consistency') is important while checking wires and connections, but not so much sensors.

 

[DSMULATOR]

I think things might be getting overcomplicated here. If a car is overheated in 37 degree temps, it sounds mechanical, not electrical. If the car is truly overheating and its not a faulty signal, are you 100% sure that the thermostat isn't in backwards or something really simple like that?

 

[XMasta19]

We like to get techical around these parts

Thank you Paul for explaining that because I might have been a tad more degrading in detailing 5v reference signals, potentiometers, thermistors, and such hehe (for future reference blitz, please don't challenge my intellenge. I by no means know everything, but I HATE the spreading of misinformation on the forums...so I at least do my research or know facts before posting)

To the OP...have we even verified that you are indeed actually overheating? If so, I would definitely say that you're most likely causing damage...aluminum heads, cold temps, overheating, warping, all are key words you should be familiar with at this point. If your fans are not operating correctly, I see you've checked sensors and such, but what about fuses/relays that power them?

 

[Locke]

Overheating while moving 40mph points away from a fan issue; the vehicles movement is providing the airflow needed.

A thermostat installed backwards (if that would be the case) isn't helpful, but alone would not cause overheating.

Have the cooling system pressure tested.

 

[Blitzeclips]

Huh?

Different sensors send information in different ways. The camshaft position sensor, crank angle sensor, vehicle speed sensor, etc. send 5V pulses - the information is encoded in the time on or off. The throttle position sensor, coolant temperature sensor and intake air temperature sensor send a variable voltage level based on changing resistance.

While you could measure the voltage going to these sensors, that will not match the voltage coming from them. The best way to check temperature sensors is to subject them to different known temperature points, then measure their resistance with an ohmmeter. There is documentation floating around which demonstrates which temperatures correlate to which resistances.

Then again, such an exhaustive analysis of the sensors is probably overkill as they're cheap and easy to replace.

Tom, I'm not sure what you're talking about exactly. Checking for continuity (kind of like 'consistency') is important while checking wires and connections, but not so much sensors.

Sensors may have been a bad example but I know when my fuel pump wasn't firing it's the first thing I checked. I wasn't being specific with my examples so sorry I didn't hit an exact 5V reference and exact sensor reference. It was a generic example. I think you're expecting a little too much from me on that one.

I would quote my Chilton's manual for this since Xmasta feels I spread so much misinformtation but I can't find it.

Look it up because it's definately a easy and effective way to find a faulty or malfunctioning unit. We use the technique all the time when diagnosing car problems. There's no coincidence it fixes the problem every single time. I'll tell you that.

 

[XMasta19]

Overheating while moving 40mph points away from a fan issue; the vehicles movement is providing the airflow needed.

A thermostat installed backwards (if that would be the case) isn't helpful, but alone would not cause overheating.

Have the cooling system pressure tested.

+1

After about 35mph, the cooling fans are no longer required. I was just curious if they are indeed working correctly or not. Let's say is fans are intermittently failing, thus causing him to overheat. It could have only taken one or two times of this happening, and he boiled over some of his coolant. Now he's low and possibly has air pockets/bubbles in the system, therefore overheating even when coolant fans aren't needed. Pressure test is awesome

 

[Blitzeclips]

+1

After about 35mph, the cooling fans are no longer required. I was just curious if they are indeed working correctly or not. Let's say is fans are intermittently failing, thus causing him to overheat. It could have only taken one or two times of this happening, and he boiled over some of his coolant. Now he's low and possibly has air pockets/bubbles in the system, therefore overheating even when coolant fans aren't needed. Pressure test is awesome

The coolant system burps itself. So go ahead and rule that one out. Please, I can't stand anything worse then people spreading misinformation on the forums..

 

[XMasta19]

The coolant system burps itself. So go ahead and rule that one out. Please, I can't stand anything worse then people spreading misinformation on the forums..

burps itself eh...so disregard my entire post because it was completely ignorant