I have a 99 blazer with the 4.3 vortec 6 cylinder...... . Im changin my head gaskets next week... New radiator, new hoses, ac delco cap rotor sparkplugs wires, lapping valves, valve seals etc...... I dont have the owners manual, looked on stickers under hood, shows diagram for fan belt, so my question is are these motors supposed to run with dexcool or the green?? I havnt bought the fluids yet im makin sure i have the right stuff for my blazer...thanks...

 

Dexcool is the correct coolant.

 

Make sure its not already the green coolant if you go with dexcool Dont mix them, bad news. If you decide to go green you will have to do a thorough flush of the dexcool

 

Thanks for the answers, but after doin some research.. Not quite sure if im gunna run with dexcool.. Ill probably stick with the green.

 

I super flushed my cooling system 3 years ago and filled it with prestone "all makes". It mixes with everything but tap water. I'm happy with it. No temp creep and my jimmy is black.

 

You'll want to have a complete set of 1/2 drive extensions (i.e. 2", 3", 4", and so forth) when you both loosen and torque those head bolts down (due to a lack of engine bay clearance). I also recommend that you use a good name brand beam type torque wrench rather than a clicker type. I'd also recommend that you replace both the head and intake manifold bolts (most, if not all, of these engines use 'torque to yield' type head/int. man bolts that are said to be good for single use only. You probably already know about the above issues, but I thought I'd mention them anyway.

And yes, you should always use the same (shortest) extension when torquing components down. But I found that doing so just wasn't possible when replacing the head gaskets with the engine 'installed' in my '95 Jimmy.

Good luck and let us know how it turns out!

 

Thanks for the info. I was aware of tty head bolts, (i have new ones) wasnt aware same issue with intake bolts, one more thing to my list. Motor still in blazer ive already seen how much room ill have to work with and i agree it would me so much easier to work on with motor out. Thank you for the info i will post the end result...

 

Indeed replace the TTY head bolts and always use an angle gauge to correctly tighten TTY bolts.

Most people on this forum reuse the intake bolts. However, it is quite important to wire brush the threads clean and chase the bolt holes in the heads (especially the blind ones) with a tap. A lot of corrosion and junk collects there and if present will alter the clamping force of the bolt. Also, the white Teflon sealer (used for head bolts) should be applied to the intake bolts as well. Then torque with an inch pound torque wrench in sequence, and go over it one more time after sitting overnight. Use only the Felpro premium intake gaskets that has molded rubber bonded to metal. NO PLASTIC.

 

I followed LesMeyer's sound intake gasket/bolt advice nearly to a 'T' about a year ago when I did a head gasket job on my thrasher '95 Jimmy (w/4.3 of course). And yes, I too reused the TTY intake bolts. The only diff was that I used Reinze (spelling ?) non-MLS (no plastic) "old school" intake gaskets. Went over the Int. bolt torque/sequence a 2nd time after 24 hours and then buttoned the rest of the thing up.

And, as Les says, the failure to chase and then thoroughly clean the blind bolt holes will, without doubt, displace much of the collected corrosion and liquid coolant/oil junk up and into the gasket and gasket surface areas as the bolts are tightened (with predictably bad results). This issue can not be over-stressed.

1967 Buick Special 2-dr with older SBC/Saginaw 4 spd conversion (a true Rat-Rod).
1970 Olds F85 2-dr (think Cutlass) w/original Olds 350 2V w/TH 350.
1986 H*nda Interceptor 700 V4 Gear Driven Twin Cam 150ish mph sport bike.
1994 883 Sp*rtster (Military Tribute project).
1995 Jimmy 4-dr 4x4 dog/grocery/hardware/lumber/trash hauler. 2012 S*baru Forester 131 mph 33+ mpg at 65 mph (wife's car, me no touch).

It's a good thing I'm retired, because I've got way too many projects. Fridge empty, add now.

 

Coolant is a real mine field. As stated above be careful because mixing Dexcool with some coolants results in brown sludge. Color schemes are not consistent to identify coolant type (IAT, OAT, HOAT, ...) and Prestone compounds the problem by not telling you what the technology is to avoid compatibility problems. Green used to mean the original IAT. Later red or orange was when the newer OAT and HOAT with their many variations (with or without phosphates etc, European vs Japanese requirements etc) started coming out but the new "compatible" Prestone is yellow or green and is almost certainly not the old IAT Prestone. I assume that the one they have that says compatible with everything is an HOAT which is supposed to have that property but I wouldn't risk it. If you ever saw the innards of a system that was mixed you would know why. Flush until clear and then pick one and remember what to top off with.

Who knew?

George