Cooling System R&R

[ittlfly]

Hey guys,

I just finished changing all the fluids in the Z. The only thing left to do is the cooling system. For years I did that service on my old 92 LT-1 so I'm not completely unfamiliar with procedures. That said, the LT-5 is some what different according to the FSM.

Last time I had it done by the dealership. I prefer to do it my self though. That way I know it is done right. Are there any ''tips and tricks'' that I should be aware before I jump into the project? Thanks in advance.

BTW I posted this over at CF too. I need all the help I can get.

[xlr8nflorida]

Originally Posted by ittlfly

Hey guys,

I just finished changing all the fluids in the Z. The only thing left to do is the cooling system. For years I did that service on my old 92 LT-1 so I'm not completely unfamiliar with procedures. That said, the LT-5 is some what different according to the FSM.

Last time I had it done by the dealership. I prefer to do it my self though. That way I know it is done right. Are there any ''tips and tricks'' that I should be aware before I jump into the project? Thanks in advance.

BTW I posted this over at CF too. I need all the help I can get.

The LT-5 can be finicky with air pockets. You need to be careful when doing the LT-5. I pour the coolant in very slowly and it works for me. Another trick is to have the car elevated as described in the article below by Marc.

Just go slow and take your time. If you rush and get air pockets, it can be a pain in the *** and if you are not careful and don't know you have an air pocket, you can do damage to the motor.

You want to only use the green coolant. They have it at Napa and it meets 1825M GM Spec. You also want to mix with distilled water only.

To be extra careful, you can measure the amount of coolant you took out compared to how much coolant you put in to make sure its equal.

Read this article in its entirety.

http://zr1specialist.com/HAT%20Web/a...%20Coolant.pdf

Good Luck

[tomcat]

I agree with the post above.
I just changed my coolant. It is very easy. I would not use none of the flushing stuff just DI water. Refill with the green coolant.

Manfred E..........
91 #906
http://pnwzr1.net

[ittlfly]

Thanks for the info guys. Aurora advised (over at CF) that about 3 gallons is removed via the radiator. I wasn't aware of that. Removing that much fluid makes me not want to open the T housing at all to get all the antifreeze out of the block. Murphy's Law seems to happen around my place and I would probably break the housing. This sure isn't my daddy's LT-1.

[sammy]

what i do to get everything filled is to remove the passenger side throttle body hose when i am filling the system back up( engine off) when i start to get a little trickle out of it .i put the hose back on and fill up the overflow all the way up and go for a little drive ,so she gets all the way warm .park her for about an hr and the system is allways full when i go ck it

[tomtom72]

I would just add some general info type stuff.

At the Grocery Store or the local beverage wholesaler you can buy Steam Distilled water in either 3 gallon or 1 gallon containers. I use a combo, it's easier to transport.

I use tap water. I live in an area that gets NYC water which is collected rain water & snow melt so it is not hard water. I use it as my flushing agent.

I drain the existing coolant, use tap water to do four flushes, running the motor up to normal temps each time. Oh, with the heat on full blast too. I then use six gallons of steam distilled water in two flushes to remove the tap water...well as best as I can get the tap water out anyway.

Then I use two gallons of steam distilled water to mix down my new 1825-M coolant to a 50/50 mix. This gives me a leftover volume to use as replacement stock during the driving season if needs be, or I have enough leftovers to make up for a gallon of new coolant mix for another flush & refill session.

I use the T-stat housing to do my drain work during my flush procedures, you may not want to do this. It just goes faster than the radiator petcock. Also, I replace my T-stat when I service the system every two years so using the stat housing make sense for me.

On using the T-stat housing as a drain point, a word of caution. The OEM bolts are a bit short that hold the halves of the housing together. Soooo, if you use the housing as a drain be aware that if you don't separate the housing from the frame mount & loosen the lower rad hose before hand you could cross thread the housing hold together bolts when you try to close the housing so you can continue flushing. If the threads get damaged don't worry as the beginning threads are the ones that get hit. ( ask me how I know )

This happens because if the housing is still attached to the frame and the hoses, the halves of the housing do not line up so well when you try to put the bolts back. The reason I say don't worry is that the bolt holes for the housing 1/2's are not blind holes. In fact they are threaded all the way out the backs of the holes....you can run a bottom tap thru them and go buy longer bolts at the parts stors in the Dorman display. ask me how I know this also!


Tom

[ittlfly]

Originally Posted by tomtom72

I would just add some general info type stuff.

At the Grocery Store or the local beverage wholesaler you can buy Steam Distilled water in either 3 gallon or 1 gallon containers. I use a combo, it's easier to transport.

I use tap water. I live in an area that gets NYC water which is collected rain water & snow melt so it is not hard water. I use it as my flushing agent.

I drain the existing coolant, use tap water to do four flushes, running the motor up to normal temps each time. Oh, with the heat on full blast too. I then use six gallons of steam distilled water in two flushes to remove the tap water...well as best as I can get the tap water out anyway.

Then I use two gallons of steam distilled water to mix down my new 1825-M coolant to a 50/50 mix. This gives me a leftover volume to use as replacement stock during the driving season if needs be, or I have enough leftovers to make up for a gallon of new coolant mix for another flush & refill session.

I use the T-stat housing to do my drain work during my flush procedures, you may not want to do this. It just goes faster than the radiator petcock. Also, I replace my T-stat when I service the system every two years so using the stat housing make sense for me.

On using the T-stat housing as a drain point, a word of caution. The OEM bolts are a bit short that hold the halves of the housing together. Soooo, if you use the housing as a drain be aware that if you don't separate the housing from the frame mount & loosen the lower rad hose before hand you could cross thread the housing hold together bolts when you try to close the housing so you can continue flushing. If the threads get damaged don't worry as the beginning threads are the ones that get hit. ( ask me how I know )

This happens because if the housing is still attached to the frame and the hoses, the halves of the housing do not line up so well when you try to put the bolts back. The reason I say don't worry is that the bolt holes for the housing 1/2's are not blind holes. In fact they are threaded all the way out the backs of the holes....you can run a bottom tap thru them and go buy longer bolts at the parts stors in the Dorman display. ask me how I know this also!


Tom

Thanks for the info but...Damn! Your engine must be clean enough to serve a 7 course dinner inside.

[tomtom72]

Originally Posted by ittlfly

Thanks for the info but...Damn! Your engine must be clean enough to serve a 7 course dinner inside.

Actually the fear of loosing head gaskets and or the heater core is what drives me to this extreme methodology for my cooling system's maintenance. I just sooooo do not want to do either job...mostly because I would never be able to do my own head gaskets, and well the heater core job speaks for itself.

I'm just a chicken!


Tom

[ittlfly]

Hey Guys...Here's an update.....I finally got a ''few minutes to myself'' to change out the antifreeze. In draining the radiator I only got approx 6 measured quarts. and....just over 2 quarts out of the overflow bottle.

Since the system holds about 15 quarts, I left about 1/2 behind in the block??. By not opening the T-stat housing I*assume* that made the difference. I don't understand why I didn't get more out via the radiator?? I guess that it will be fine since the coolant is changed out every year. (done in previous years by the dealer).

I did however use the coolant sold at Napa auto supply that meets GM 1825-M mixed 50/50 with distilled water. Maybe next year I'll be brave enough to crack the T-stat housing and get most of the coolant flushed out.

BTW..no problems on the refill with air blocks. I did do the filling real SLOW though.

[xlr8nflorida]

I would not worry about it as every 2 years is still relatively good maintenance.

Right now you are looking at 50% new coolant and 50% 1 year old which is great maintenance.

If you really want to be OCD, you could swap it out again in the spring or mid summer.

You could also do what I've done before which is unorthodox.

When I drive my car, and after it cools down, I suck out the reservoir and add fresh 50/50 distilled water and coolant and then put the radiator cap back on. Takes 5 minutes.

You should still change it the ole fashioned way However, if you get behind in your maintenance your coolant will always be in good shape.

I change coolant out fully then use my topping off method which keeps the coolant in perfect shape. However if you only got 50% you can use same method and get about 75% fresh coolant in there without too big a cost. If you want to get to 100% its much tougher as the law of diminishing returns comes into play.

On my other Vettes, I change the coolant every year or 2 years at the most even the LS1 running Dexcool which is supposed be good for 5 years.