[jogasz28]

After buying my 68, I noticed the thermostat housing leaked slightly. Today I picked up a 160* stat and gasket. Drained the coolant, removed the housing and found it was a Taiwan O-ring style housing. I replaced the stat and used the original o-ring. Of course it leaked. I then tried using the full face gasket on the o-ring housing, it also leaked. I then got a used full-face gasket style housing and new gasket. It leaked. I put a straight edge across the housing gasket surface and found it was bowed (could see light in the middle). I trued the surface as best I could by file. I didn't have another gasket, so I used the red hi-temp gasket-maker. Put it together and I'll let it cure overnight, fill and test it in the morning.

Now my question: Will the gasket maker be good enough without a gasket for the thermostst housing?

[supv26]

Probably not. I ran into the same situation and the only cure was a new water neck. I went ahead and bought another chromed neck and used the O-ring. I did not put turn the mounting bolts too tight and so far it doesn't leak. I do have a GM OEM water neck on order at the dealership and when this one starts to leak I will replace it with an origninal style cast iron neck. I will have it powder coated before i install it so it will look nice.

[JohnZ]

Work the (non O-ring) housing back and forth on a piece of emery paper on a piece of glass until the witness marks on the bottom are even all the way across so you know it's flat, then install it with a GM #10105135 gasket (has a molded-in silicone bead) and it won't leak - no sealer required.

Also, swap the 160* stat for a 180* stat; the 160* will do nothing at all for cooling (stat only controls MINIMUM temperature, not operating temperature), and if you have enough radiator to bring it down to 160*, that's not hot enough to let the oil heat up enough to boil off condensate and combustion by-products; that stuff is acidic, and forms sludge.

[deerhunter]

I have had the same problems with those o-ring housings. As far as I am concerned they are a piece of xxxx-dirt. I have even tried using both the o-ring and gasket. All this time I thought I was the only one having this problem. Maybe I will try the factory type too.

[jogasz28]

Originally Posted by jogasz28

After buying my 68, I noticed the thermostat housing leaked slightly. Today I picked up a 160* stat and gasket. Drained the coolant, removed the housing and found it was a Taiwan O-ring style housing. I replaced the stat and used the original o-ring. Of course it leaked. I then tried using the full face gasket on the o-ring housing, it also leaked. I then got a used full-face gasket style housing and new gasket. It leaked. I put a straight edge across the housing gasket surface and found it was bowed (could see light in the middle). I trued the surface as best I could by file. I didn't have another gasket, so I used the red hi-temp gasket-maker. Put it together and I'll let it cure overnight, fill and test it in the morning.

Now my question: Will the gasket maker be good enough without a gasket for the thermostst housing?

I got lucky for now. The next day I filled the system and put 100 miles on the car. No leaks....yet.

[mr. black]

Wow, I've had the same problem ever since I bought my 69. My problem is that I also have an Eldelbrock. No other "correct" neck will clear my temp sending unit. I have even "made" a hose to fit with a chrome neck that I think is supposed to go to an older model car. It goes straight instead of to the driverside. But of course I still have the same leaking problem and I tried everything that has been listed to correct it. What is the part number for the GM neck and will it clear the temp. sending unit? Moving the unit to the side is not an option due to the different size hole and my headers. Unless there is very small unit that will fit this (383) 350 block.

[PinMd]

Same problem with the o-ring style. I went to advanced auto parts, they had a OE style cast unit for a sbc, it had a hole in the top for a sensor of some sort, but came with the plug to fill the home. I think I paid around $14 fot it. Works like a charm.

[Camaro Dave]

Originally Posted by mr. black

Wow, I've had the same problem ever since I bought my 69. My problem is that I also have an Eldelbrock. No other "correct" neck will clear my temp sending unit. I have even "made" a hose to fit with a chrome neck that I think is supposed to go to an older model car. It goes straight instead of to the driverside. But of course I still have the same leaking problem and I tried everything that has been listed to correct it. What is the part number for the GM neck and will it clear the temp. sending unit? Moving the unit to the side is not an option due to the different size hole and my headers. Unless there is very small unit that will fit this (383) 350 block.

I had that same problem with the temp sending unit being in the way of the radiator hose. I bought a swivel water collar and it clears the sending unit with no problems.

The water collars that have the O-rings do work. You shouldn't use the O-ring and silicone since that would be like using a double gasket. Just make sure that the intake manifold surface where the water collar meets is clean and smooth.

[Steptoe]

These chrome units are desposable, O ring or gasket.
The 0 rings last longer but never reuse the O ring, get a new one from the local hardware store.
If u look carefully u will notice stress marks in the top, if these are pesent, replace.
They also corrode out after a few yrs.
If u REALY want a more perminent neck, use one of the old stock cast units.

Temp sender clearance...these come in big bulky and small ones...use a small one with a brass thread adapter

[mr. black]

THANX. I'll try that.