I've got a bad feeling

[Mendozart]

My cousin called me today saying her car overheated ( 93' 525ia ). She says she noticed the needle in the red, then decided she was only 10 minutes away from her destination and decided to continue on:( She said she also got a check engine light after the overheating. Does this mean she blew the headgasket? ( coolant in exhaust, killing the oxygen sensor ). I'm going to check it out this weekend.

[Bill R.]

she just noticed that the needle was in the red, implying that it could have been there for quite some time.. and then drove ten minutes more..I'd say yeah, there's a very good chance that it blew the head gasket and possibly cracked the head as well as cracked the block. The check engine light doesn't have to come on from coolant. I'm pretty sure that on the m50 if it exceeds a certain temp the dme will retard the timing and richen up the mixture to try and get the engine to cool down which will in turn light the check engine light since the mixture won't be anywhere near what it should be.





My cousin called me today saying her car overheated ( 93' 525ia ). She says she noticed the needle in the red, then decided she was only 10 minutes away from her destination and decided to continue on:( She said she also got a check engine light after the overheating. Does this mean she blew the headgasket? ( coolant in exhaust, killing the oxygen sensor ). I'm going to check it out this weekend.

[SnakeyesTx]

1993 Engine BMW 525 i 2.5L,AOD,CALIF,RUNS, 190-195 ME0009 (stock #) $800 Sierra Auto Recycling, Inc. USA-CA(Ridgecrest) Request_Quote 1-800-346-8733 Request_Insurance_Quote

1995 Engine BMW 525 i MT 060095 (stock #) $750 KHS Auto Dismantling USA-CA(Rancho-Cordova) E-mail 1-877-859-2630

1993 Engine BMW 525 i 2.5L, 110K 6M126 (stock #) $Call 3M Auto Dismantling USA-CA(San-Jose) E-mail 1-408-998-8661


Plan on it. :(

The stock #'s are the yards inventory stock numbers for your reference.

These 3 were found on car-part.com and I chose California because of your profile. Sorry to hear it :(

[Mendozart]

Okay, so I was able to check my cousins car today. No oil in coolant, no coolant in oil. No smoke when starting up. Ran the car for at least 15 minutes and it actually stayed a little below operating temp. Found out she had her AC on when it overheated, so i started it again with AC on. It started to creep toward red zone. I figured I would for sure replace thermostat, thermo housing (metal one). She was going to look through records to find out when water pump was last replaced. Top hose was hot and bottom hose was cool. AC drive belt is cracking will replace both belts anyways. Did have one code, it was a 1223 (coolant temp sensor) Should I do a compression check? Thanks for any suggestions.

[pundit]

Okay, so I was able to check my cousins car today. No oil in coolant, no coolant in oil. No smoke when starting up. Ran the car for at least 15 minutes and it actually stayed a little below operating temp. Found out she had her AC on when it overheated, so i started it again with AC on. It started to creep toward red zone. I figured I would for sure replace thermostat, thermo housing (metal one). She was going to look through records to find out when water pump was last replaced. Top hose was hot and bottom hose was cool. AC drive belt is cracking will replace both belts anyways. Did have one code, it was a 1223 (coolant temp sensor) Should I do a compression check? Thanks for any suggestions.
Did it dump all the coolant out when it appeared to overheat?
If it didn't then the chances are no major damage was done to the head or block.
Different story if she drove it for 10 minutes with no coolant at all!

[gmannino]

I think you got lucky with this one. Sounds like the coolant temp sensor needs to be replaced. How do you know for sure the car was overheating? did it steam up at all? was it trying to boil over? It might just be a faulty temp sensor acting up and making the needle jump to red.

[Jon K]

Wow that's luck - sounds like it may be a coolant temp sensor. Ohm it out vs bentley and see what it reads.

[Mendozart]

Yeah, I'm thinking it's the temp sensor myself. They (my cousin and her husband) said they had to add some coolant, but there was no evidence of massive coolant loss. I'll be checking that sensor first.

[Mendozart]

The only thing that happened was she saw the needle in the red. There is no evidence of overheating though. Will check the sensor first.

[Mendozart]

Yeah, I'm thinking it's the temp sensor myself. They (my cousin and her husband) said they had to add some coolant, but there was no evidence of massive coolant loss. I'll be checking that sensor first.
Could this sensor(ECT) cause false readings, where it thinks it's overheating, but is not? After further investigation , I found out that my cousin only had to put in about 12 ounces of water to reservoir. The only symptoms of overheating was the temp gauge reading. I will be checking the resistance of the sensor hopefully today.

[Bill R.]

2 temp sensors, one for the dme to read and one for the gauge to read. You stated yourself that the gauge crept up once you turned the ac on which is likely if there's a cooling system fault such as not auxillary fan working when the ac is on and the condensor pressure is getting high..

As far as the 12 ounces of water, did your cousin bleed the system and make sure that all the air was out. And check it again the next day since frequently trapped air will keep it from taking all the coolant that it can.



Could this sensor(ECT) cause false readings, where it thinks it's overheating, but is not? After further investigation , I found out that my cousin only had to put in about 12 ounces of water to reservoir. The only symptoms of overheating was the temp gauge reading. I will be checking the resistance of the sensor hopefully today.

[Mendozart]

I'll go ahead and check the resistance of sensor first ( for code 1223 ). After that I'll go ahead and bleed system, and check for aux fan function while running air con. Why do you think I got 1223 code though? Is this a result of overheating?

[Mendozart]

So I checked the sensor today with the engine totally cool. It measured 4.3k Ohms. the table listings are 14 deg F 7-11.6k Ohms / 68 deg F 2.1-2.9k Ohms / 176 deg F 0.27-0.40 k Ohms. So it's probably bad. However, as I warmed the car up to check aux fan functionality, the car started to creep towards the red again. I shut it down and could hear a hissing sound. I saw a slight trickle of coolant by upper hose. As I checked connection the hose just popped off. About a good inch of the radiator cracked off in the hose. So, it will be getting a new radiator, water pump, thermostat & updated thermo housing. I'm still wondering about that ECT sensor though.

[Mendozart]

So I checked the sensor today with the engine totally cool. It measured 4.3k Ohms. the table listings are 14 deg F 7-11.6k Ohms / 68 deg F 2.1-2.9k Ohms / 176 deg F 0.27-0.40 k Ohms. So it's probably bad. However, as I warmed the car up to check aux fan functionality, the car started to creep towards the red again. I shut it down and could hear a hissing sound. I saw a slight trickle of coolant by upper hose. As I checked connection the hose just popped off. About a good inch of the radiator cracked off in the hose. So, it will be getting a new radiator, water pump, thermostat & updated thermo housing. I'm still wondering about that ECT sensor though.
So I replaced radiator, water pump, thermostat, thermostat housing, upper & lower hoses and drive belts. The culprit was the thermostat, it was all busted up. Got it all done, now I can start my 2 week vacation with a good feeling:D

[GoldenOne]

wow, im glad to hear this, you (more likely your cousin) really lucked out! 2nd chances are awesome, wish i could get some more often...just let her know if it ever approaches red again to stop no matter how close the destination is

[BillionPa]

turn on the heater and run fan in pos 4 too.