Great forum, learned a few things just lurking the last few weeks.
First post but I'm sure there will be many more.

I need to flush the coolant system, is it ok to open drain **** on radiator and put water hose in fill reservoir and crank car to flush out? Or is it better to drain and fill and repeat?
Also, everything I've red said the 1990 L98 use the green coolant. This car has orange. What should I use?

Thanks

 

Sounds like Dex Cool but I didn't think they started using that till 95 or 96? Wonder if someone retrofitted?

That stuff hit me hard in a super nice 1996 S-10 truck I had. Ate the water pump up and clogged the block. Cost me quite a bit to fix at a point in my life that I really didn't have that money to spare!

 

To truly flush the coolant system you need to remove the knock sensor in the block and the plug on the other side of the block. Just opening the petcock on the radiator will not clean out the block. Remove the sensor and the plug and run water thru the radiator....engine NOT running. Once you have clean water coming out the block then open the petcock on the radiator as you continue to run water thru the engine block.

Since you think you have orange coolant, look for a coolant that will mix with both orange or green...it is out there.

 

Thanks for the info.
But if the system is cleaned out and no coolant is left why would I need to find a coolant that will mix with both orange and green?
Sorry for the newbie question but I've always let Ford work on my trucks and never had to do anything like this.

 

The difference in the two are the corrosion inhibitors they used which turn to jello if mixed. I would think you would be find with going to green once everything is flushed out as long as you do a really good flush. I would.....

 

am I missing something here? seems from the prestone site, this stuff http://prestone.com/products/antifre...t/product_list

seems to me, a good flush and a fresh 50/50 fill is all that is needed.

 

Pull your heater core hoses and flush both ways.

 

Can you elaborate please?

 

What engine do you have in your 90? And what coolant do you use?

 

L98 and prestone concentrate ( http://prestone.com/products/antifre...t/product_list ) - add 2 gallons to my system and top off with water (approx. 50/50 mix). flush and fresh 50/50 mix about every 5 years. BTW, same with the iron head L98 in my 85....

FWIW, I installed a prestone flush kit on the hose from the heater core to the throttle body, to flush the system.




pretty much using that setup for years since my early C3 days. never a problem....

 

This is the best way to flush a system. Hook up a hose to it and turn the hose on 50% start the car and let it run until the water coming out is crystal clear. Truly is the only way to get a complete system flush.

When you refill make sure there is no air in the system and you will be fine.
The whole dex-cool is garbage talk I really don't understand I hAve seen dexcool cars with 300k and everything is fine. As long as you change the dexcool every few years and no air in the system you are fine.
Do not believe the "dexcool will last 100,000 miles" all coolant should be flushed every 2-3 years.



QUOTE=Joe C;1593842388]L98 and prestone concentrate ( http://prestone.com/products/antifre...t/product_list ) - add 2 gallons to my system and top off with water (approx. 50/50 mix). flush and fresh 50/50 mix about every 5 years. BTW, same with the iron head L98 in my 85....

FWIW, I installed a prestone flush kit on the hose from the heater core to the throttle body, to flush the system.




pretty much using that setup for years since my early C3 days. never a problem....



[/QUOTE]

 

Chad,

The owners manual will tell you the correct antifreeze to use.

I would also suggest spending a extra few dollars to mix the antifreeze at a 50/50 ratio yourself with distilled water. Distilled water does not have the minerals, chlorine and other chemicals found in tap water that causes the scale and buildup. If you use distilled water your cooling system will stay clean.

 

I appreciate the help.

 

Yea the service manual said to use green coolant, that is why I was confused when it had orange in it and when I was at the Chevy dealer getting a spare key made, I told him I also needed a gallon of coolant for it and he gave me orange.

 

I beg to differ on the Dex Cool talk being garbage. It was a proven fact that the rust inhibitors used degraded many of the plastic components used within the cooling system and created havoc. Yes, they improved the formulation of both the plastic and the coolant but trust me, it was a massive problem on the early cars. I most definitely wouldn't put Dex Cool in a pre Dex Cool era car and think it would work.

 

If still unsure the new Prestone is guaranteed to work in any vehicle and mix with any antifreeze. Comes in concentrate or pre-mix.

 

Do not get the mix get the full and mix with distilled water much better price needed just under 4 gallons for my 94. Be sure to pull the knock and what ever you have on the other side and leave them out till your ready to fill.

 

we need to make a post on the correct way to COMPLETELY drain and flush a cooling system. I did this on my 85 and it worked like a charm. but it takes a full week to do to really get a deep "clean" (that includes driving around with prestone flush mix after the initial flushing has occured. dissolving of scale). If your system is not rusty and bad and gross (you will know that answer to this by looking into your overflow tank.....is it clean? if not then you will have scale/rust inside the system. You can choose to do a complete "douche" or not. I did it and it was sssssoooooooooo good for the car.

in your first post you asked about being good enough to fill with the hose and run the car and then drain again.

problem with that is that the thermostat is going to keep closing on you when you introduce cold water into the system again which stops the system from circulating.

so part of a complete drain involves either copius amounts of time waiting for the thermostat to reopen, or, you quickily pull the termostat out and replace the housing with the gasket but no thermostat.

that is the best way. then you can drain and fill with an idling car and do a good job.

as ant says, even better is to have the knock sensor pulled. you can search posts here to see guys who have built hose systems with the splitter valves to let the house water run into the block from the bottom up (through the ks) then you let the car ciculate, and then you open the other side of the splitter and let the water drain from the block. keep refilling it and draining it with the tstat out.

then, fill with a bottle of prestone douche, and drive it for a week. then repeat the same douching process. you will have a descaled system if you do this.

 

Good info guys thanks.
I think while I am at it, I'm going to replace upper and lower radiator hoses and heater hoses. And since I'm going to take the thermostat out when I flush it, I will go ahead and replace it as well.
I've located the knock on the passenger side but haven't located the plug on the drivers side yet. It's a tight fit on that side, plus it was dark light night when I was looking for it.

 

Good idea. A little preventative maintenance is never a bad idea.