Working on little things, may have some questions soon

[1991 Corvette ZR-1]

Ended up going after my old oil cooler lines which have increased their leaking and what a fight that was. So I finally got a chance to take Jerry?s cooler lines out the parts bin and get ready to install. I do not advise trying this with the radiator shroud in place unless you are okay with a teaspoon of oil dribbling down the radiator. Had to pick up a 29mm socket and notch it to fit around the filter housing to get a good grip on the top fitting. They were on there! Used a two foot breaker bar plus a four foot cheater bar on it to break these things loose from the housing.

Anyway, figured I would post some pictures of what I am working on and also ask some questions as I work on some other parts of the Z. I do not have anything like what the factory used to seal the threads of the fittings. I do have permatex aviation sealant. Will this suffice? Worked well on the oil pressure sensor threads but these are considerably larger.

Next after the new oil cooler lines, I will be replacing the AC condenser, dryer, all AC specific O rings and oil in the compressor. Planning to recharge with R134 once I have put everything back together. AC blew room temp air since I first got it and the system was completely flat.

[1991 Corvette ZR-1]

Alright not to overthink things but I want the reassurance I am using the right stuff for this application. Jerry?s instructions say to use pipe thread sealant. I have permatex aviation sealant on hand. Does not appear to have a size limitation on the fitting sealed. Will this stuff work or is there a different product that should be used on the new fittings for the oil housing?

[1991 Corvette ZR-1]

Alright, put a pin in the question about proper thread sealant but I believe I will use permatex aviation thread sealant. Can someone school me on the AC switches? The FSM is not the most helpful on this part. I believe the black switch per the FSM is the AC compressor pressure switch, but does not state if high or low. The red switch is referred to as AC compressor engine cooling switch.

Then there is what I assume is the high pressure switch on larger tube on the upper part of the evaporator. What is what? Also, these are the old R12 switches so I am guessing they will not be compatible with R134a correct? Not sure what switches to replace these with. Would like some suggestions.

[1991 Corvette ZR-1]

Lots of views but I can?t be the only person who has gone through these parts before around here. Maybe it is some tough love to find the answers myself. Well find them I did! I leveraged my resources and reached out to Marc, who was kind enough to inform me of the answers to my questions. So I must confess, I got so engrossed in figuring out the AC switches, I glossed over the sealant provided in the FSM for resealing the oil cooler line fittings to housing.

It is Loctite 565. Marc informed me of this as well and it was only after reviewing the installation procedure again that I discovered this was there the whole time. So, loctite 565 has been ordered and on the way.

Next were the various switches on the AC hard lines. Again, these are per Marc who is an outstanding resource for everything on these cars. The large switch on the large upper tube to the evaporator, which I thought was high pressure switch is actually the low pressure switch and the replacement part is Four Seasons 35751. The red switch is the engine cooling switch per FSM and the replacement for it was Four Seasons 36669. The black switch was an over pressure compressor clutch cut off switch and not a direct replacement on that one short of a junkyard trip. And, you guessed it, I ordered all the switches I could.

Things are escalating. I was able to remove the oil psi sensor from the housing but the replacement sensor I have is a 92-95 sensor. So I will have to figure that out. I also unplugged the low oil psi alert switch connector and it is covered in oil! So, I may be taking off the remote oil filter housing entirely, as the water pump hose is out of the way along with everything else. I am also contemplating replacing the spectra radiator I have with a Dewitt?s single row now that all coolant is drained. Hmmm?

[Mystic ZR-1]

Go with the DeWitts 2 row radiator.
Fits great and has the extra cooling capacity.

[conesare2seconds]

Thanks for posting the AC switch info.

[1991 Corvette ZR-1]

Originally Posted by Mystic ZR-1

Go with the DeWitts 2 row radiator.
Fits great and has the extra cooling capacity.

The double row is tempting. The current $100 Spectra seems to do a great job for my style of driving. From what I have read, the single row version is even greater cooling capacity over the factory rad. So the double row drops in with minimal to no modifications? I think I may continue to run the spectra rad for a while longer. I also got looking at the SPAL fan kit on Dewitt?s site. I think between the single row and the fans I would be at about $1,000. I do not track so maybe the double row is overkill?

I took the oil filter housing off. As expected, it was filthy. Look what I have access to now, the oil pressure regulator cover. Now I can change that gasket as well as the sight hole plug seal for the passenger side head. I do not think tightening those 8mm bolts did too much for the tiny leak it was appearing to have. Glad I bought the gaskets in advance. I will also restore the wiring harness running through here as it is oily and beyond filthy. Ordered some high temp split loom that mimics the factory coverings.

You know, I have to remove the plenum to pull the compressor. If I am that far into it, maybe now is a good time to eliminate the secondaries. Is there any HP to be found in the elimination? If any, I figure a couple at the most? Quite the rabbit hole from what was supposed to just be changing oil cooler hoses.

[Norwegianmopar]

Originally Posted by Mystic ZR-1

Go with the DeWitts 2 row radiator.
Fits great and has the extra cooling capacity.

I just bought the 2 row Pro Series for our car. Marc Haibeck told be it would be a very good replacement if I was buying a new one. Probably more than I need, but what the heck, I am upgrading more that isn't a must do because I want to [emoji16]

Sent from my SM-G955F using ZR-1 Net Registry mobile app

[1991 Corvette ZR-1]

Originally Posted by Norwegianmopar

I just bought the 2 row Pro Series for our car. Marc Haibeck told be it would be a very good replacement if I was buying a new one. Probably more than I need, but what the heck, I am upgrading more that isn't a must do because I want to [emoji16]

Sent from my SM-G955F using ZR-1 Net Registry mobile app

Did it fit without isssue? Maybe you and Mystic are onto something. It is only a few hundred bucks more than the single row. I could have sworn I read something about fitment issue for double row but maybe that was an earlier model years ago. Guess I will look into the double row.

[secondchance]

Based on my experience, dual-row Dewitt, Spal fans and 200 amp alternator (to deal with Spal fans' increased draw) makes coolant overheating concern in 90 plus temp days thing of the past.