Automotive radiator flush

[Tynee]

Good morning. I bought a '95 4Runner for my son's first vehicle. We're rebuilding the engine right now before he turns 16 at T-Giving.

The PO dumped what looks like a 50 gallon drum of stop leak in the cooling system. Anybody got any recommendations for effective DIY methods to clean the radiator out before we reinstall, or do I just need to find a radiator shop or even replace it completely?

 

[toyotadriver]

Good chance your radiator and your heater core is plugged. ***** when people use that garbage.

You could try setting up a pump system and circulate some solvent to try to clean it out. You will probably be better just putting a new radiator in. Hope your heater core isn’t plugged but good chance it is.

 

[Makoto]

if the motor was all apart i assume it got a good flush, i'd get a new radiator and water pump and make sure to flush the heater core real good before sticking the motor back in. there's lots of stuff to do it but water would be the first thing i'd try.

that'll also tell you if the heater core needs to be swapped as well.

 

[Tynee]

Yeah, hadn't thought about the heater core. Block went to the machine shop, so it's nice and clean now. Trying to be sure we build something that will reliably get him through college, so may just go ahead and replace the rad now, and leave the heater core bypassed until we're ready to replace it, too.

 

[toyotadriver]

Yeah, hadn't thought about the heater core. Block went to the machine shop, so it's nice and clean now. Trying to be sure we build something that will reliably get him through college, so may just go ahead and replace the rad now, and leave the heater core bypassed until we're ready to replace it, too.

Try to run water through the heater core. If it flows through it could still be plugged partially but at least you’ll know if a replacement heater core is in your future. It might be ok too.

 

[JeepYJ]

Do you know why they had stop leak added? Maybe the radiator or heater core is bad.
My son bought a Ranger earlier this summer that had a leaking radiator from small cracks in the plastic side tanks. The PO had added leak stop. We used some radiator flush and filled and dumped the cooling system 4-5 times until it was draining mostly clear. Installed new radiator and had been running fine, heater works good too.

 

[Tynee]

Do you know why they had stop leak added?

Massive head gasket failure. Pretty common on Toyota V6's of this variety.

 

[theoldwizard1]

I use Preston's Super Flush. (2 bottles on my old E150 with rear heat.)

• Drain the old coolant
• Refill with (city) tap water and flush If you are on a well, I would buy distilled water.
• Drive for about 30 minutes with heater on
• Drain
• Refill with water and drive another 30 minutes
• Drain
• Repeat
• Fill with STRAIGHT, NON-DILLUTED, coolant. I do NOT top off/burp the system.
• Drive another 30 minutes (watch the temperature gauge) and then let fully cool
• Once fully cooled (overnight is best) check the level strength
• Top off with tap water or diluted coolant

Yes, it is a long process.

 

[gizardlizard]

Massive head gasket failure. Pretty common on Toyota V6's of this variety.

Nailed it. I know this motor very well. Do not use the stock head gasket either. There are some designed to help alleviate this issue. Even more important than the water pump is the timing belt. Change it since your doing the water pump. Be sure to only use an Aisin Brand pump. This year probably already has the hydraulic tensioner. Pretty sure they went to the hydraulic over the spring in 1992.

 

[mrbill55]

Good morning. I bought a '95 4Runner for my son's first vehicle. We're rebuilding the engine right now before he turns 16 at T-Giving.

The PO dumped what looks like a 50 gallon drum of stop leak in the cooling system. Anybody got any recommendations for effective DIY methods to clean the radiator out before we reinstall, or do I just need to find a radiator shop or even replace it completely?

Replace the radiator, it will be the smarter way to go.

I also agree, you might want to replace the heater core at the same time, as it too is gummed up with the old stop leak.


Bill S.

 

[Tynee]

Nailed it. I know this motor very well. Do not use the stock head gasket either. There are some designed to help alleviate this issue. Even more important than the water pump is the timing belt. Change it since your doing the water pump. Be sure to only use an Aisin Brand pump. This year probably already has the hydraulic tensioner. Pretty sure they went to the hydraulic over the spring in 1992.

I have the new water pump, the new timing belt, new oil pump, complete gasket set, all Toyota/Aisin parts. New ARP Head bolts, new Mahle crush washers should arrive today...

I've read that the new Toyota HG's have corrected this issue, that Toyota was replacing these under warranty for a long time with an upgraded design, which is all you can buy these days. Any thoughts on that?

Also going to headers to eliminate the crossover pipe dumping heat on the #5 cylinder and cooking the HG there.

 

[gizardlizard]

That’s awesome. Didn’t know they updated the head gasket. You are definitely going about this the right way. Using all high end components. That motor will outlive you when done.

 

[djbmw]

As others have said, its in your best interest to buy a new rad and heater core vs wasting time "cleaning" them out.

 

[Chickenpants]

Hot tanking ain’t what it used to be, make sure all the water passages are cleared. I had a Ford 200 straight six, when the block was decked the stop leak machined just like metal. I didn’t figure it out until I had the head off two more times!

 

[Tynee]

Hot tanking ain’t what it used to be, make sure all the water passages are cleared. I had a Ford 200 straight six, when the block was decked the stop leak machined just like metal. I didn’t figure it out until I had the head off two more times!

Good advice. Thanks.

 

[charbar]

No doubt in your situation I would just replace the radiator and heater core and be done with it. No worries then.

 

[CraigStu]

I'd look into replacing the heater core and decide depending on how hard it is. Some cars have a cover plate on the side of the heat/AC box so the core just slides out. Others you have to take out the whole box and disassemble which may require dash removal. I see you are in 'Heart of Bluegrass' territory so maybe it doesn't get too cold there so maybe a 50% heater function might be livable?

 

[PWC Repair]

It's a '95 model..........just replace the heater core as it will fail soon anyway.

 

[619DioFan]

I also have a 95 runner w/ 3.0 . radiator is not that pricey. I would replace it along with the heater core and all hoses.