The plague of coolant leaks


jeffcoslacker
03-09-2012, 11:01 PM
170,000 must be the magic number for '97 Luminas, at least mine....I put a water pump and serp belt on it at 70,000, just for piece of mind as my wife was taking out of town years ago, and I figured at that mileage, that was where the most likely breakdown would come from, if it did.

I replaced the bypass hose a couple of years ago when it sprung a pinhole, and the upper radiator hose shortly after just because it looked pretty sorry.

That has been the extent of cooling system repairs. Now passing 170K, the thermostat went bad and wouldn't hold heat when when cold outside, I had to put a radiator in last week, the left tank cracked. Now the heater core is leaking slightly, and I have a small seep from someplace on the back of the motor (i.e. flywheel end) that is terribly frustrating to find....and as you probably know, I know most of the tricks. I can tell you what it ISN'T...it is not:

LIM
Thermostat o-ring
Heater/throttle body pipe
Throttle body hoses
Throttle body casting
...or anything else I can see in the suspect area...

I can't find any source or trail, the only clue is a smell of coolant after a long ride, and there is a small "divot" in the top of the starter solenoid that always has a drop of DexCool sitting in it after a run.

I guess I'll get under it and see if it's a block freeze plug or something. Feel free to offer any suggestions in case I'm forgetting something else in that general area....

McLin
03-10-2012, 01:22 AM
170,000 must be the magic number for '97 Luminas, at least mine....I put a water pump and serp belt on it at 70,000, just for piece of mind as my wife was taking out of town years ago, and I figured at that mileage, that was where the most likely breakdown would come from, if it did.

I replaced the bypass hose a couple of years ago when it sprung a pinhole, and the upper radiator hose shortly after just because it looked pretty sorry.

That has been the extent of cooling system repairs. Now passing 170K, the thermostat went bad and wouldn't hold heat when when cold outside, I had to put a radiator in last week, the left tank cracked. Now the heater core is leaking slightly, and I have a small seep from someplace on the back of the motor (i.e. flywheel end) that is terribly frustrating to find....and as you probably know, I know most of the tricks. I can tell you what it ISN'T...it is not:

LIM
Thermostat o-ring
Heater/throttle body pipe
Throttle body hoses
Throttle body casting
...or anything else I can see in the suspect area...

I can't find any source or trail, the only clue is a smell of coolant after a long ride, and there is a small "divot" in the top of the starter solenoid that always has a drop of DexCool sitting in it after a run.

I guess I'll get under it and see if it's a block freeze plug or something. Feel free to offer any suggestions in case I'm forgetting something else in that general area....

Welcome to the Club. I have repoaced a lot of stuff. I have a small leak and didn't see amything. But I smell too the coolant if the engine is warm. I have refill all 14 days a cup of coolant.

Tech II
03-10-2012, 09:15 AM
Coolant dye will leave a trace somewhere....

Blue Bowtie
03-11-2012, 09:29 AM
Unfortunately, about all you have left off your list is core plugs and head gaskets.

Tech II
03-11-2012, 02:59 PM
Hard to believe you have not replaced LIM's on this, especially since:

"the only clue is a smell of coolant after a long ride, and there is a small "divot" in the top of the starter solenoid that always has a drop of DexCool sitting in it after a run."

Plus you do say the heater core is leaking....

Also, the coolant is suppose to be changed every 5 years/100K, whichever comes first, so has the coolant been flushed and replaced 3X's by now?

jeffcoslacker
03-11-2012, 07:29 PM
Hard to believe you have not replaced LIM's on this, especially since:

"the only clue is a smell of coolant after a long ride, and there is a small "divot" in the top of the starter solenoid that always has a drop of DexCool sitting in it after a run."

Plus you do say the heater core is leaking....

Also, the coolant is suppose to be changed every 5 years/100K, whichever comes first, so has the coolant been flushed and replaced 3X's by now?

LIM gaskets replaced when the car was less than a year old under warranty...before I owned it. Yes, coolant exchanged at least that many times....

I noticed that wet spot on the starter before the radiator went out...tried to find it, and ultimately discovered the seep in the radiator tank starting. At that point I figured since it was roughly straight back from the leak, it might be blowing back there as it dripped off the underside of the upper hose...but apparently, it was a separate issue. I had a real good view of the intake and head gasket seams on that end when I had it all stripped down to replace the thermostat...didn't see anything telling from that angle at least...

Tech II
03-11-2012, 10:46 PM
Intake gasket was replaced in '98........look under the power steering pump on the passenger side, and look underneath the throttle body on the driver's side, especially the depressions in the top of the block where the coolant can collect.......

rkvons
03-12-2012, 01:30 PM
One other source of leak to consider is your timing chain cover. This gasket gets dried out over time. I have a '98 Monte with 184K on it and I had to replace that gasket last December. It showed itself by leaking down the back side of the engine and accumulating on the motor mount on the passenger side. It's an $8 fix and 6 hour job.

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