I discovered how to easily drain the oil cooler! (on my 91' at least)

[WVZR-1]

Originally Posted by Jagdpanzer

I had my oil cooler out when I swapped in my new motor and it did not have any kind of plug like the OP mentions.

Cooler by application part #'s is '90 - '93 and '94 & '95 a different part #.

'90 - '93 = 14104653

'94 & '95 = 10219643

[Schrade]

Originally Posted by Blownrunner

I serviced the engine to nine quarts, the FSM says the engine requires about 10.5 with filter change and cooler drain, I started the car and the oil pressure came up at the same time period (actually a little faster, used Amsoil 10W-30 instead of 5W-30). Drove it around the block and I will check it tomorrow. Weird, but I believe I had less chain chatter using the 10W-30, or it was my imagination. I didn't like doing an oil change and the oil immediately turns dark when it mixes with those last two quarts.

Seems kinda' strange that pressure would come up faster, after a change, with the cooler drained too... ... especially if air would only compress, before pushing through.

Dave; is tube configuration different for the 2 different coolers?

[Dynomite]

Originally Posted by Blownrunner

It seems that everyone accept that the oil in the oil cooler does not get changed during a routine oil change. Did you know, according to the FSM, that the oil cooler holds 2 quarts of oil, about 20% of the oil in the engine?

Determined, I figured out how GM solved this problem: The oil cooler has a drain plug that is easily accessible on the passenger side of the car, aft of the center front spoiler, in the center of what appears to be a large grommet with an allen screw in the middle! Mine was covered up by some type of sealant or adhesive, which is easily removed. The grommet is actually the lower right mount that sandwiches the oil cooler/air conditioning condenser assembly in the front cooler assembly housing.

I am sharing this because it seems to be accepted practice that you don't drain the oil cooler at oil change time. I would be astonished if I were the first to discover this, or at least to post it on this forum.

Great Info........

Originally Posted by WVZR-1

I believe the "conventional wisdom" needs to prevail here because the plug the OP mentions isn't meant to be a "service port". I don't know the thread size involved here but for any thing other than maybe it's use to drain the oil for a cooler change seems maybe foolish. Any conventional engine oil drain plug uses a gasket or seal to prevent seepage and I'm quite sure this could only be some sort of an NPT plug and that's not a conventional method used for engine oil service ports.

Excellent Conventional Wisdom
I would expect that the flow through the Oil Cooler is of such significant velocity/pressure that contamination deposits would not STALL in the bottom of the Oil Cooler. Such accumulation of contamination deposits could over time close off the oil cooler. My thinking is that such deposits would be cleared by force (oil pressure and hydrodynamic cleaning) within the oil cooler narrow passageways. I am also thinking the Oil Cooler Flow is Filtered just after the Oil FIlter (just thinking).

Originally Posted by A26B

If I recall correctly, the oil cooler is not in the full flow path until the oil temp thermostat in the oil filter adapter opens. Prior to opening, the oil flow to/through the oil cooler is minimal, so that when the oil t-stat does open, the cooler is fully charged.
That is why you will not see any abnormal pressure lag after an oil change with an empty oil cooler, as mentioned by the OP.

I am assuming that this oil goes to the Oil Cooler after the oil temperature has opened the oil temp thermostat directly from the Oil Filter. I would assume that this oil is newly filtered oil having passed through the Oil Filter Adapter Housing.

Originally Posted by WVZR-1

Cooler by application part #'s is '90 - '93 and '94 & '95 a different part #.
'90 - '93 = 14104653
'94 & '95 = 10219643

I LIKE Part Numbers

Originally Posted by Jagdpanzer

I had my oil cooler out when I swapped in my new motor and it did not have any kind of plug like the OP mentions.

Great Additional Information
Meaning that Oil Cooler Part # 10219643 (94' and 95') does not have the Drain Plug.
This Oil Cooler information is for a your 1994 I am assuming

[A26B]

If I recall correctly, the oil cooler is not in the full flow path until the oil temp thermostat in the oil filter adapter opens. Prior to opening, the oil flow to/through the oil cooler is minimal, so that when the oil t-stat does open, the cooler is fully charged.

That is why you will not see any abnormal pressure lag after an oil change with an empty oil cooler, as mentioned by the OP.

[BlackWidow#2]

Originally Posted by A26B

If I recall correctly, the oil cooler is not in the full flow path until the oil temp thermostat in the oil filter adapter opens. Prior to opening, the oil flow to/through the oil cooler is minimal, so that when the oil t-stat does open, the cooler is fully charged.

That is why you will not see any abnormal pressure lag after an oil change with an empty oil cooler, as mentioned by the OP.

Hi Jerry, That is exactly what I was thinking as I read this post. In my opinion, you are 100% right on. George

[Schrade]

Originally Posted by A26B

If I recall correctly, the oil cooler is not in the full flow path until the oil temp thermostat in the oil filter adapter opens. Prior to opening, the oil flow to/through the oil cooler is minimal, so that when the oil t-stat does open, the cooler is fully charged.

That is why you will not see any abnormal pressure lag after an oil change with an empty oil cooler, as mentioned by the OP.

Oil THERMOSTAT???

Is this a service-able item, that warrants a maintenance eye?

[Jagdpanzer]

I agree with Jerry that the oiler cooler is only in the flow path when the oil temp thermostat begins to open. As I mentioned above my 94 model year oil cooler did not have any kind of a drain fitting. For flushing the cooler I filled it with clean solvent through the inlet and return ports at o-ring flange connection then shaked the cooler back and forth to work the solvent through the tubes then cleared it with compressed air. Initially I was surprised how many times I had to repeat the process until the solvent came out clear. Appears to me that over time and miles thickened oil and the usual oil born sediments accumulate in the bottom cooler header tube. After thinking about it I do not find this unusual. If this were an oil cooler from a industrial engine like we see at work no attempt would made to clean it. Instead it would be replaced with a new cooler.

[WVZR-1]

Originally Posted by A26B

If I recall correctly, the oil cooler is not in the full flow path until the oil temp thermostat in the oil filter adapter opens. Prior to opening, the oil flow to/through the oil cooler is minimal, so that when the oil t-stat does open, the cooler is fully charged.

That is why you will not see any abnormal pressure lag after an oil change with an empty oil cooler, as mentioned by the OP.

Jerry - That's what I recall Tyler mentioning also and I didn't comment BUT had this question. If you drain 60 oz of oil and add 60 oz to the conventional fill the crankcase is 60 oz overfull until the t'stat opens which I thought Tyler mentioned as "seldom"? The 60 oz "over-fill" I think needs to be considered here as "compromised" and possibly "catastrophic". I used a 60 oz number assuming that was what might be measured in the draining not anticipating the 64 oz capacity as "gospel".

So your only option would be to do the conventional fill and then watch for a "low level" on the dip stick? I just can get past the "conventional" wisdom that has prevailed for years.

Am I missing something?

[Schrade]

and this is good info too...

Originally Posted by Jagdpanzer

I agree with Jerry that the oiler cooler is only in the flow path when the oil temp thermostat begins to open. As I mentioned above my 94 model year oil cooler did not have any kind of a drain fitting. For flushing the cooler I filled it with clean solvent through the inlet and return ports at o-ring flange connection then shaked the cooler back and forth to work the solvent through the tubes then cleared it with compressed air. Initially I was surprised how many times I had to repeat the process until the solvent came out clear. Appears to me that over time and miles thickened oil and the usual oil born sediments accumulate in the bottom cooler header tube. After thinking about it I do not find this unusual. If this were an oil cooler from a industrial engine like we see at work no attempt would made to clean it. Instead it would be replaced with a new cooler.

PW - you think it was really the chunky stuff? Or just the old oil?

[Jagdpanzer]

Another point, the oiler cooler by itself does not account for all the oil that cannot be drained. The oil cooler volume on my 94 is around 1.4 quarts.