what engine coolant should I use?
Melting Slicks
Joined: Dec 2004
Posts: 3,284
Likes: 51
From: Jacksonville, FL
St. Jude Donor '08 thru '26
I would think that your 91 came with 1825-M GM spec coolant.
GM part number is: 12378560
This is a silicated type coolant, not to be confused with the OAT, organic acid technology, coolants that came later in the 90's as DexCool.
Sometimes a pure silicated coolant is hard to find at the parts store as they are more toxic than the OAT stuff.
If you drain and flush the system completely till your flush water runs clear you should be okay to use the newer OAT or the HOAT coolants, Hi-bred Organic Acid Technology.
I would strongly urge you to not mix any silicated coolant with either the OAT or the HOAT coolants.
Tom
GM part number is: 12378560
This is a silicated type coolant, not to be confused with the OAT, organic acid technology, coolants that came later in the 90's as DexCool.
Sometimes a pure silicated coolant is hard to find at the parts store as they are more toxic than the OAT stuff.
If you drain and flush the system completely till your flush water runs clear you should be okay to use the newer OAT or the HOAT coolants, Hi-bred Organic Acid Technology.
I would strongly urge you to not mix any silicated coolant with either the OAT or the HOAT coolants.
Tom
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
You car uses ehtlyene glycol for coolant. That's the green color stuff. Most places have a universal coolant but go with the standard coolant.
Buy the concentrated gallon jugs. I have found that most of the so-called "ready-mix: coolants (already in a 50-50 mix) are only a buck a gallon less than the concentrated stuff. So buy the concentrated coolant, use distilled water to create your own 50% mix and save money. You can get distilled water at any grocery store for about a buck a gallon.
I have always been a Prestone user but it's getting hard to find the green Prestone. If you have a CarQuest store nearby, get their "Prime" coolant. It will work fine.
Buy the concentrated gallon jugs. I have found that most of the so-called "ready-mix: coolants (already in a 50-50 mix) are only a buck a gallon less than the concentrated stuff. So buy the concentrated coolant, use distilled water to create your own 50% mix and save money. You can get distilled water at any grocery store for about a buck a gallon.
I have always been a Prestone user but it's getting hard to find the green Prestone. If you have a CarQuest store nearby, get their "Prime" coolant. It will work fine.
