Cooling Concerns

[bayleif]

I have recently noticed a couple of symptoms related to the cooling system of my 280 that I fear will soon need to be addressed. I’ve been trying to ignore them since the one thing the cooling system is doing well is cooling the engine. These symptoms, in the order that I’ve noticed them:
1) When I open the cap on the overflow tank, pressure is released; even though the car has not been started for a week. Is this normal?
2) I find that I have to add coolant regularly, but there is never puddle under the car.
3) Yesterday, when I used my finger to check the coolant level (the engine was cold!) the coolant left a black oily slim on my finger. However, there is no coolant in the engine oil.
I think this points to the water pump, but I want to get second opinions. If so, how big a deal is it to change the water pump?


Chuck Bartlett
1969 Signal Red 4 Speed

[al_lieffring]

quote:Originally posted by bayleif

I have recently noticed a couple of symptoms related to the cooling system of my 280 that I fear will soon need to be addressed. I’ve been trying to ignore them since the one thing the cooling system is doing well is cooling the engine. These symptoms, in the order that I’ve noticed them:
1) When I open the cap on the overflow tank, pressure is released; even though the car has not been started for a week. Is this normal?
2) I find that I have to add coolant regularly, but there is never puddle under the car.
3) Yesterday, when I used my finger to check the coolant level (the engine was cold!) the coolant left a black oily slim on my finger. However, there is no coolant in the engine oil.
I think this points to the water pump, but I want to get second opinions. If so, how big a deal is it to change the water pump?


Chuck Bartlett
1969 Signal Red 4 Speed

Chuck

These are not symptoms that point to a leaky water pump.

A water pump would be leaking coolant onto the ground under the front of the motor.

My concern is that the oily film in the coolant suggests that combustion gasses are leaking past the head gasket into the cooling system.

First I would suggest having the cooling system pressure tested. If no external leaks are found, then a combustion chamber pressure test should be done.

This is done by installing an air hose into the spark plug hole with the piston at TDC. Pressure is applied to the chamber to see it any pressure is leaking into the cooling system. I would even go so far as to suggest testing cylinder #4 first, from my experience this is the most likely place to find problems on an M130e motor.

Most of the coolant that leaks past a head gasket is burnt in the combustion chamber and wouldn't show up in the motor oil. This burning of the coolant can cause severe damage to the aluminum cylinder head and piston top. So the car should NOT be driven untill this problem has been found and repaired.

I hope that you only find a leaky water pump!

Al






113-042-10-014715
built 11 Jan 66
904/396 blue, Ivory Tex
condition- rust bucket

[bayleif]

Al,
Wow, this doesn't sound good. Thanks for the info, it'll keep me from doing any additional damage. I'll update this thread as I learn more.


Chuck Bartlett
1969 Signal Red 4 Speed

[n/a]

Baylief

One other possibility.  I had a similar problem with a 2.3 4 cylinder engine - oil in the coolant overflow tank.  It turns out that the head gasket had failed between an oil passage and a water passage.  Since the oil is under a higher pressure than the coolant, oil is forced into the cooling system.  This type failure will not show up on a cylinder leakdown test.  

I am not sure if these engines have the same close proximity of oil and coolant passages.  Anyway, this is something to think about.

Good luck  

Iverson

[bayleif]

Iverson,
Thanks. Either way, the head has to come off. I'll do the pressure tests first, then if that's inconclusive; ponder anew.

Chuck Bartlett
1969 Signal Red 4 Speed