Coolant and Spark Plug gap questions.

[Pmac]

I need some advice on adding/replacing coolant for my 1975 Pontiac Parisienne (‘Cheviac’) and a plug gap query.
I have a weep in the passenger side rad tank fitting that receives the upper trans cooler line flare nut; the rad has to come out to re-solder the female fitting; when I complete the repair, I will have to add coolant. The coolant present is clean, and safe down to – 50; however, it is a dark peach colour (images attached). The coolant recovery tank hose has an odd slimy residue, and the hose material is soft and swollen. Can I add Universal Coolant, or do I have to flush the system? I have universal coolant in rest of my antiques roadshow. The “GM compatible" products available at Canadian Tire are only compatible back to 1996.
As a Canadian Pontiac the engine is a 400 SBC “Orange Engine” code U (images attached); I will be replacing the plugs this winter with AC Delco R44TXs, (1975 only) gap of 60 thou. I am wondering if a gap of 35 to 45 thou might be an improvement. Thanks, Pete.

 

[AuroraGirl]

I need some advice on adding/replacing coolant for my 1975 Pontiac Parisienne (‘Cheviac’) and a plug gap query.
I have a weep in the passenger side rad tank fitting that receives the upper trans cooler line flare nut; the rad has to come out to re-solder the female fitting; when I complete the repair, I will have to add coolant. The coolant present is clean, and safe down to – 50; however, it is a dark peach colour (images attached). The coolant recovery tank hose has an odd slimy residue, and the hose material is soft and swollen. Can I add Universal Coolant, or do I have to flush the system? I have universal coolant in rest of my antiques roadshow. The “GM compatible" products available at Canadian Tire are only compatible back to 1996.
As a Canadian Pontiac the engine is a 400 SBC “Orange Engine” code U (images attached); I will be replacing the plugs this winter with AC Delco R44TXs, (1975 only) gap of 60 thou. I am wondering if a gap of 35 to 45 thou might be an improvement. Thanks, Pete.

looks like someone used Dexcool in that.
If your rad is coming out, may be a good idea to get it cleaned and tested for leaks. Dexcool isnt bad per se, but copper/brass radiators benefit from the abrasive short term use of green coolant. Being it looks clean, its probably not been in there all that long or if it has its been sitting more than circulating.
A good flush and fill with green would be my recommendation. The hoses should be replaced , all that exist due to age and swelling. most of the universal coolants from the store are Dexcool but different label different name. Not all.
But if yoiu want to maintain universal coolant in your fleet, then post up what one you use and we can give a recommendation one way or another. But generally speaking.. if that coolant isnt corrosive to lead and solder, then its probably OK

 

[AuroraGirl]

I need some advice on adding/replacing coolant for my 1975 Pontiac Parisienne (‘Cheviac’) and a plug gap query.
I have a weep in the passenger side rad tank fitting that receives the upper trans cooler line flare nut; the rad has to come out to re-solder the female fitting; when I complete the repair, I will have to add coolant. The coolant present is clean, and safe down to – 50; however, it is a dark peach colour (images attached). The coolant recovery tank hose has an odd slimy residue, and the hose material is soft and swollen. Can I add Universal Coolant, or do I have to flush the system? I have universal coolant in rest of my antiques roadshow. The “GM compatible" products available at Canadian Tire are only compatible back to 1996.
As a Canadian Pontiac the engine is a 400 SBC “Orange Engine” code U (images attached); I will be replacing the plugs this winter with AC Delco R44TXs, (1975 only) gap of 60 thou. I am wondering if a gap of 35 to 45 thou might be an improvement. Thanks, Pete.

the .060 gap sounds like it would be hard on your ignition but i heard GM tried this with a few small block lines

 

[82sbshortbed]

I gap my 454 plugs at .045 and it seems to work better than .035. I use the green coolant in my square too.

 

[82sbshortbed]

Also I had the orange coolant in my 2000 camaro SS and it got slimy too as you mentioned. Idk why but it was all over the long plastic dipstick. That's how I found out and changed it.

 

[Bextreme04]

I would drain, fill with water and coolant flush and then run it up to operating temp and drive it a bit to clean it out, then drain before pulling the radiator for repair. Then replace with universal green long life.

My 67 Buick Riviera with a 455 uses R44TS plugs and I have them gapped at .045. Runs like a champ. I agree .060 is likely to be hard on a standard HEI distributor with a standard plug like the R44

 

[Pmac]

I would drain, fill with water and coolant flush and then run it up to operating temp and drive it a bit to clean it out, then drain before pulling the radiator for repair. Then replace with universal green long life.

My 67 Buick Riviera with a 455 uses R44TS plugs and I have them gapped at .045. Runs like a champ. I agree .060 is likely to be hard on a standard HEI distributor with a standard plug like the R44

As I recall - '75 was the first year - at least in this part of the world - for HEI across the board, and the big gap was a hope to reduce n0x emissions ('X' suffix). The pressures are fairly high - but the ratio is quite low, so I should be able to advance the timing to 'what the motor wants'. They went to .045 the next year so I reckon I should be safe with that. Good straight-ahead advice on the flush, coolant is so expensive I was hoping to sneak by, but so it goes. Gosh, a ' 67 Riviera! I bet it does run like a champ.

 

[Bextreme04]

Good straight-ahead advice on the flush, coolant is so expensive I was hoping to sneak by, but so it goes.

I only brought it up since you are pulling the radiator anyways, so you will need to buy some regardless. It is probably cheaper to buy brand new green coolant than to try and hope you got the same stuff already in there. A gallon of Prestone extended life universal coolant from walmart is only $11/gal and I just mix it 50/50 with a gallon of distilled water. That should fill most systems.

Gosh, a ' 67 Riviera! I bet it does run like a champ.

It's pretty roadkill right now. Lots of rust and cosmetic issues, but all the parts are there. It has the original switch-pitch TH400 from 67 in it still, but someone put an original 1970 high compression Riviera 455 in it at some point in it's life with a holley 4-barrel and an MSD ignition. It ran so well when I first got it that I had accidentally forgotten to connect an entire bank of spark plugs and it fired right up and ran on only one bank of the engine. I got it cheap because it hadn't been on the road since 1997 and wouldn't hold coolant. I just got all of the coolant stuff repaired and will hopefully have the motor back in it this weekend. It had obviously not had antifreeze in it at some point and had frozen. Missing several freeze plugs, one plug rusted through on the back of the cylinder had and drivers side cylinder head externally cracked into the water jacket from freezing. It got a JB weld repair on the head and all new freeze plugs, filled it all up with water and pressure checked the entire system up to 20psi with no leaks.. so it's back into the car and on the road until I get the itch to put some more power into it with some aluminum TA heads and a big cam. Until then its just going to get some basic functional exterior improvements and get the interior redone so we can cruise in it as a family next summer.

 

[AuroraGirl]

I only brought it up since you are pulling the radiator anyways, so you will need to buy some regardless. It is probably cheaper to buy brand new green coolant than to try and hope you got the same stuff already in there. A gallon of Prestone extended life universal coolant from walmart is only $11/gal and I just mix it 50/50 with a gallon of distilled water. That should fill most systems.



It's pretty roadkill right now. Lots of rust and cosmetic issues, but all the parts are there. It has the original switch-pitch TH400 from 67 in it still, but someone put an original 1970 high compression Riviera 455 in it at some point in it's life with a holley 4-barrel and an MSD ignition. It ran so well when I first got it that I had accidentally forgotten to connect an entire bank of spark plugs and it fired right up and ran on only one bank of the engine. I got it cheap because it hadn't been on the road since 1997 and wouldn't hold coolant. I just got all of the coolant stuff repaired and will hopefully have the motor back in it this weekend. It had obviously not had antifreeze in it at some point and had frozen. Missing several freeze plugs, one plug rusted through on the back of the cylinder had and drivers side cylinder head externally cracked into the water jacket from freezing. It got a JB weld repair on the head and all new freeze plugs, filled it all up with water and pressure checked the entire system up to 20psi with no leaks.. so it's back into the car and on the road until I get the itch to put some more power into it with some aluminum TA heads and a big cam. Until then its just going to get some basic functional exterior improvements and get the interior redone so we can cruise in it as a family next summer.

Do you mean prestone universal that is green-like in appearance? A little more neon, maybe yellow but still a green. the bottle has a black and yellow label on a yellow jug?
If so, I have been using it in my F150 after flushing and it seems to be working ok. the neon yellow makes for needing to double check visually the level since its not very contrasted to the plastic jar
but i got unlucky last time I went to walmart, had no green but they had lots of that. I got concentrate and distilled water because the price hurt at the time lol

 

[AuroraGirl]

You must be registered for see images attach

not shown well in this photo but this coolant was opaque, you couldnt see through it like you should be able to. hard water and 2 types of coolant + some corrosion and junk from a boat anchor + a couple years
also found a pic of the coolant I asked about

You must be registered for see images attach

I only brought it up since you are pulling the radiator anyways, so you will need to buy some regardless. It is probably cheaper to buy brand new green coolant than to try and hope you got the same stuff already in there. A gallon of Prestone extended life universal coolant from walmart is only $11/gal and I just mix it 50/50 with a gallon of distilled water. That should fill most systems.



It's pretty roadkill right now. Lots of rust and cosmetic issues, but all the parts are there. It has the original switch-pitch TH400 from 67 in it still, but someone put an original 1970 high compression Riviera 455 in it at some point in it's life with a holley 4-barrel and an MSD ignition. It ran so well when I first got it that I had accidentally forgotten to connect an entire bank of spark plugs and it fired right up and ran on only one bank of the engine. I got it cheap because it hadn't been on the road since 1997 and wouldn't hold coolant. I just got all of the coolant stuff repaired and will hopefully have the motor back in it this weekend. It had obviously not had antifreeze in it at some point and had frozen. Missing several freeze plugs, one plug rusted through on the back of the cylinder had and drivers side cylinder head externally cracked into the water jacket from freezing. It got a JB weld repair on the head and all new freeze plugs, filled it all up with water and pressure checked the entire system up to 20psi with no leaks.. so it's back into the car and on the road until I get the itch to put some more power into it with some aluminum TA heads and a big cam. Until then its just going to get some basic functional exterior improvements and get the interior redone so we can cruise in it as a family next summer.

 

[Grit dog]

@Pmac, generally orange colored (or yellow, pink, purple, blue) are some type of OAT or HOAT coolant. Since not all are compatible with others and you have no way of determining what’s in it, even though it looks very clean and clear in your pic, you’re saving potential future issues by dumping it.
As said above, best way is to clean and flush it before you do the (minor it appears) repairs. And then refill with the coolant of your choice.

 

[Ricko1966]

@Bextreme04 I owned a 67 riviera for about a day I don't even remember what engine was in it.Stock were those 435s or 455s ?Anyway like 16 years old bought it from some kid at school who's grandad probably gave it to him. I only bought it cause it would roast the back tires unbelievably,took it home,Dad said take it back. Damnit

 

[Pmac]

This is precisely what I was after - I wondered if there was a simple and cheap test available to determine if this was the OAT or HOAT formulae; I bought this car from the son and heir of the original owner, they took remarkable care in most aspects of the maintenance - although the son thought he was selling me an SBC that had a bad lifter and valve seals ( it was a loose E.F.E. valve and a perished shift modulator) - so I am sure they used 'the good stuff'. I will start stocking up on concentrate antifreeze - it is about 20 USDs a gallon here; and will next consider what rust inhibitor to put in solution with the water during the flush. Thanks for the input Grit dog, I should have put that at the start but not that adroit with the posting.

 

[mrdap]

I also concur with the 0.45-in gap for HEI.
And I also concur with the green coolant.
As suggested by others, be sure to completely drain and flush one or more times with fresh water before switching from orange to green.
I believe they are incompatible with each other.
I recommend a 50-50 mixture of distilled water and the green style coolant.
Distilled water is preferred to tap water.