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Recently purchased 1973 Oldsmobile Omega. Original 1 owner with 82,000 miles. We knew the radiator was bad upon purchasing the car. We installed new 3 core radiator and are confused with correct way to install thermostat. I know that the way flows into radiator thur the top hose, so does the thermostat fit with the plunger side in the manifold or plunger side in the thermostat housing. The picture in the 73 service manual is confusing.
We are having issues with car overflowing thur the vent hose on the radiator as well, and since it does not have a overflow we will have to install one. Any suggestions on where to purchase one for 73 omega.
Welcome, nice picture of correct t-stat install, when you fill with antifreeze leave radiator cap off till it is full with no bubbles. Nice looking car.
I also noticed that my lower radiator hose has no spring in it. Should the lower hose have a spring in it to prevent it from collapsing? Could this be a culprit to the car running hot, Pump works, new 3 core champion radiator, new thermostat, just trying to pin down heating issue.
Back in 1972, I bought a new 1973 Nova SS. The car was raced at the drag strip weekly. I learned that AC cars had an overflow bottle and spoiler under the radiator, so I added those. Omega would have been the same. They repro the bottles, you can get them on ebay. I don't know if your car had a spring or not. But same thing, you can grab one off ebay for 7.00 free ship. It can't hurt anything.
Normally the reason they spew coolant out the overflow is because the radiator was over filled. There needs to be some head space, approx. 2". There is a fill line on the rear of the radiator below the neck. The reason for the head space is to allow room for the coolant to expand. Without the head space it will muscle past the cap and wind up on the ground.
Normally the reason they spew coolant out the overflow is because the radiator was over filled. There needs to be some head space, approx. 2". There is a fill line on the rear of the radiator below the neck. The reason for the head space is to allow room for the coolant to expand. Without the head space it will muscle past the cap and wind up on the ground.
Other reasons are a bad cap or blown head gasket.
Not in a vehicle with a recovery/overflow tank..
They are easy to make, 3" pcv 8" tall(or less), a cap glued to the bottom, and a screw on top cap, with a bulkhead connector in it , hose from rad to the bulkhead connector, and then hose into the pvc "tank" 1" from the bottom..
paint it black
I use a union that is for plastic hose, as the bulkhead connector.
cheap and easy to make, no reason to have an overflow hose dumping on the ground ever Period..
not hard to make removable for those chalk mark judging events either .
My next one will be alum. made out of a wide format printer drum that is 4" round 50" long.
Cut it down to needed length , weld a bottom on it. and a screw on cap. polish optional..
Last edited by midnightleadfoot; Feb 25, 2018 at 11:57 PM.
On recovery tank system the radiator cap allows the coolant to flow in and out of the radiator dependent on pressure as it warms, flows out of the radiator, or vacuum as it cools allows it flow in. You fill the recovery tank as you would a late model car. With an overflow (puke bottle), the bottle needs to be emptied periodically and you still have to remove the cap to fill.
Get a Robertshaw type thermostat if you can find one. RS itself has been out of automotive t-stat business for some time but a couple of manufacturers still use their design. It's the most accurate and reliable I've found. 180 or 195 degree, your choice. Either will work fine.
Make sure you have the correct 15 psi radiator cap for car without coolant recovery. As stated, fill radiator to about 2 inches below fill neck and the system should work as designed without puking.
I hate to tell you to flush your new radiator but odds are good if the rad was bad, the rest of the system needs attention too. Remove the t-stat, get one of those Prestone kits and backflush the block and heater core with clear water till things clean up. If it doesn't clean up, you'll have to use a chemical cleaner.
After everything's clean, refill with 50-50 coolant mix preferably mixed with distilled or deionized water. Some say it makes no difference over tap water but I haven't had near the cooling system maintenance issues since I started using purer water.
John, when I took the OEM t-stat out of my 350 I noticed it was labled which side went up. I guess the new stuff doesn't do that anymore.
Hey Allan, I agree with you I've seen some with that stamped on them. But I've also seen some without it. You know how I like pictures though! Less chance of someone misunderstanding if they're looking at a photo vs. reading what I'm trying to communicate.
'73 had a coolant recovery tank available which was different than '72. It needed a bracket and bolt at the bottom of the reservoir to complete the installation.
I have run my 72 in south Florida with A/C on for 10 years and never spit a single drop. If radiator filled as per above and cooling system works correctly, you don't need an overflow.
Thanks for sharing, have to admit, I never even heard of this car, looks cool!
1973 was the first year of the Omega. It was the Olds version of the Chevy Nova, Pontiac Ventura and Buick Apollo. Amazing how few interchangeable parts they share though.
When I purchased my '73 Omega, it didn't have an overflow tank and I noticed that it was spitting antifreeze on the ground. So I went to Classic Industries and purchased the tank in the attached picture. It bolted right into the factory holes in the fender.
Last edited by 72hardtop; Mar 4, 2018 at 09:09 AM.
Recently purchased 1973 Oldsmobile Omega. Original 1 owner with 82,000 miles. We knew the radiator was bad upon purchasing the car. We installed new 3 core radiator and are confused with correct way to install thermostat. I know that the way flows into radiator thur the top hose, so does the thermostat fit with the plunger side in the manifold or plunger side in the thermostat housing. The picture in the 73 service manual is confusing.
We are having issues with car overflowing thur the vent hose on the radiator as well, and since it does not have a overflow we will have to install one. Any suggestions on where to purchase one for 73 omega.
Thanks BIll
Very interesting how your body side molding runs the entire length of the front fender, mine stops before the wheel well. I also noticed that yours is located higher on the side of the body, (probably to clear the front wheel opening?)
When I purchased my '73 Omega, it didn't have an overflow tank and I noticed that it was spitting antifreeze on the ground. So I went to Classic Industries and purchase the tank in the attached picture. It bolted right into the factory holes in the fender.
Right, that's what I said to use. That is mounted on the wrong side I believe, from my old memory. Personally, I don't consider $50.00 a big deal for a stock looking item that will function perfectly and look attractive under the hood. Sure you can make one from PVC, you can use a Coke bottle held with duct tape. Both cars looks GREAT!
Right, that's what I said to use. That is mounted on the wrong side I believe, from my old memory. Personally, I don't consider $50.00 a big deal for a stock looking item that will function perfectly and look attractive under the hood. Sure you can make one from PVC, you can use a Coke bottle held with duct tape. Both cars looks GREAT!
Yes, I did have to mount it on the driver's side as my air conditioning lines were affixed to the passenger side wheel well. Just needed some extra hose and it works great, looks factory.
The attachment picture isn't my car, (I wish), but it shows the tank on the drivers side.
Very interesting how your body side molding runs the entire length of the front fender, mine stops before the wheel well. I also noticed that yours is located higher on the side of the body, (probably to clear the front wheel opening?)
One of those is probably dealer installed which was common back in the 70's. Body side moldings, pinstripes and paint sealant were common dealer items to increase profit. I would guess the full length one is the dealer installed but just a guess.
Thanks for the pictures of the overflow tank. Looks good. As far as the molding goes, could it be due to my vehicle was originally a vinyl top that they took off, so maybe the base vehicle had the side molding go all the way forward?
