Engine overheating

[QTIP]

hi everyone,

Last week my '91 beretta 2.2 suddenly started overheating, and upon checking why i found out my cooling fan wasn't turned on.

I've already checked the motor of the fan by connecting it straight onto the battery and it worked fine so the fan motor isn't at fault, but for some reason it won't turn on anymore. I've checked the wires and can't find anything abnormal for as far as i can see the wires.
Also i checked the ECM, and got codes 33 and 45, not related to the fan. reset the ECM, no effect.

Also i replaced the upper radiator hose yesterday as the old one had a large swelling in it. refilled fluids, still no fan.

So only thing i can think of is the fan relay. So i just ordered one at my local chevy dealer and i should come in tomorrow or day after, but i have no idea where it is.

So can anyone tell me where the fan relay is located? (i checked with the dealer and he said it's not one of the 4 relays against the firewall.

And/or if you think something else might be at fault for causing the fan not to turn on?

Hope to get some help soon!!!

Thanx,

QTIP

[Jeff P]

I'd guess fan relay too unless your ECM just isn't turning it on for some reason (bad ECM).  The coolant fan relay *is* on the relay bracket on the firewall, and should be the 2nd from the passenger side.  4 wires, colors are red, black/red, pink/black, and dark green/white.  I hope you get it figured out

[QTIP]

Thanx for the reply Jeff.
The realy should come in 2morrow or the day after.
However, i just couldn't help from looking under the hood again a few minutes ago, and on the '91 2.2L engine it has 2 sensors right above the coolant inlet into the engine on the side of the engine block. i thought the bottom one was the coolant temperature sending unit, since when i pulled this plug out my temp. meter went all the way to 0. But just now with the engine idling i pulled the top plug and suddenly the fan turned on! The engine also stuttered a little bit, and i got a code 15 right after. Code 15 says in the haynes manual: "Coolant sensor or circuit/ low temperature indicated"
But since the fan turned on it tells me that it might not be the relay...??? So then it could be the temperature sending unit, but which one? the top one or the bottom one? and what is the difference between the 2?

hope anyone can help!

Thanx

-QTIP

[Guest]

(QTIP @ Feb. 07 2007,09:38)QUOTEand on the '91 2.2L engine it has 2 sensors right above the coolant inlet into the engine on the side of the engine block. i thought the bottom one was the coolant temperature sending unit, since when i pulled this plug out my temp. meter went all the way to 0. But just now with the engine idling i pulled the top plug and suddenly the fan turned on! The engine also stuttered a little bit, and i got a code 15 right after. Code 15 says in the haynes manual: "Coolant sensor or circuit/ low temperature indicated"
Beleve you answered your on question.
You said "i thought the bottom one was the coolant temperature sending unit, since when i pulled this plug out my temp. meter went all the way to 0."
Yep thats to the temp gauge.

Then you said "i pulled the top plug and suddenly the fan turned on!"
Thats probably the temp sensor for the fan and is probably the source of your problem. But also check the connection. It may have gotten corroded or the connector itself is bad. But more than likely its the sensor.

FYI those relays are all the same and you could have swapped one for the other to see if it was bad.

[QTIP]

ummm sounds obvious hehehe... now that you put it like that! THANX!

Fortunately the relay was only €16,50.

I guess i'm gonna try to order one of those sensors, hope those aren't too expensive either... For some reason the haynes manual only talks about the bottom sensor, not the top one. But i assume there's gonna be just as much coolant loss from the top one as the bottom one when i unscrew it.

I'm also assuming there's no way to repair or clean one of these sensors?

Either way, maybe this is a nice case for others who might experience the same problem in the future.

Thanx for all the help!

-QTIP

[Jeff P]

Since the fan comes on when you remove the plug (which is normal), that means the ECM still has control of the fan, which means your cooling fan relay is good, which means BerBeatter92 is probably right about the sensor or connection.

[QTIP]

ok so i ordered a new sensor today, although i hope it's the right one cuz the guy wasn't sure which one of 2 it was in the computer, but he said i could return it if it's the wrong one..

However... one other thing i have going on for awhile is that i was getting a code 33 and/or 34 about the map sensor, which i replaced today because it was making a ticking noise when i turned on my a/c. However now that i replaced it, i still  get the ticking sound, and now i'm starting to wonder if maybe it's one of the relays behind the map sensor. And since i already have a relay!.... But now i want to know out of those 4 relays that are against the firewall, which one is which? and can somebody confirm BerBeatter92's comment that all those relays are interchangeable/ the same?

(1991 beretta 2.2L L4)

[Guest]

(QTIP @ Feb. 08 2007,09:26)QUOTEand can somebody confirm BerBeatter92's comment that all those relays are interchangeable/ the same?
Pretty easy to find out actually. Theres a manufacture part number on the bottom of the relay. If there all the same then so are the relays.

[QTIP]

ok, i replaced to MAP sensor, i replaced the fan relay which seems to be working now (fingers crossed), but the ticking persists.

I'm guessing it's another relais (i think the one for the a/c compressor) However, i tried changing that one with the new one, and noticed that they are all ticking, just cuz 1 is broken (i think) So hopefully another new one will solve the problem.
I just hope i don't have to change out my alternator, cuz i read somewhere that faulty relays can be traced back to a busted alternator or voltage regulator.

I'll keep you all updated!

[Guest]

If you can get ahold of a VOM (Volt/Ohm Meter) you can test to see if you altinator is working properly. Simpliy check the voltage on the battery with the car running. If its around 14v's and doesnt fluctuate the alt is good. Also check it with the lights on, radio on, AC fan on high, windshield wipers on. What this will do is put a high load on your alt and if the regulator is good it should hold the voltage around 14v. But while your at it check/clean your grounds and battery connections too as this can also play havoc with your eletrical system.

[QTIP]

ok i will do that, although i've done it before a couple of months ago, and it said around 14v at the battery terminals with the engine running. However, i'm not sure if i checked it with a/c on etc.

Also i'm pretty sure that my battery might need replacement as i don't think it is holding charge, as it takes a long time to start in the the morning, but not when i start it again right after it has been running. When i start i see my volt gauge dropping down almost to 8v.

Seems like all my problems that i've posted about all seem to be connected or interrelated in one way or another heheh, but at least now i'm figuring out why...

Thanx again for all the help. I'll post with updates on the cars condition.

[Guest]

Two checks you can do on your battery are:
Pull the battery out and look at the sides. If the sides are bulged/expanded (not straight/square) its time for a new battery.

Another test is if its not a sealed battery and you have caps on top, with the battery connected and the car running, pop the caps off and see if you have bubbles in each cell, this may take a couple of minutes to happen.  If there is no bubbles in one or more cells then that cell is not charging and the battery is going dead. Also check the acid level in each cell. Each cell should almost be full.

Becareful not to get the battery acid on you or your clothes.