hpinson

Hi. After a blown head gasket in my 95 3VZE i am about to flush the cooling system. Have settled on a powdered dishwasher detergant flush.

Bought a Prestone flush kit, and there is a plastic T-adaptor to be installed on the engine to heater hose, for hooking up the low pressure garden hose.

I want to make sure that I have identified the correct hose. Is it the the hotter hose that enters the firewall on the drivers side that I tap, or the cooler one that exits on the passenger side?

It's pretty hard to trace these!

oldsub86

Two suggestions

1. it probably does not matter which hose

2. the Prestone kit should tell you which one to use

hpinson

Yes, the Prestone kit suggests "Hose 2 that runs from firewall to engine". However, unlike on my simple F150, where hoses run straight on top of the engine, it is not at all clear which of the two hoses this is. Both hoses appear to snake off under the engine and I have not been able trace either or find a good diagram.

Any confirmation that is does not matter? I can't really see why it would.

My current thinking is that the driver's side hose, which runs hotter, is the one to tap.

Jake94

Look at the 2 hoses running from the engine to the firewall. In one of the hoses you should see a valve, w/ a control cable on it, this is your heater control valve. When you move the control on the dash it opens the valve allowing hot water to flow through the heater core.

Look on top of the valve and there is an arrow showing the direction of the coolent flow. Using this info install the "tee" as in the directions in the kit.

OR, make it simple and replace the valve w/ the "tee" and flush the system per the directions. Replace the valve when done. No cutting and you eliminate the possibility of the tee leaking and leaving you stranded.

My $0.02, Jake

Gadget

You are not really going to put powdered diswasher machine detergent in your engine are you? Please say I miss read that.

Gadget

hpinson

Not in the engine-- in the cooling system to flush out the oil residue from a blown head gasket, since repaired. This seems pretty well accepted -- to use a measured amount of non-foaming detergent (powdered Calgon seems perfered) well mixed with water for a short time, say 15 minutes, then rinse, rinse, rinse-- followed by a refill with the Toyota Red coolant/water in a 50%/50% ratio.

See the current thread:

http://www.pirate4x4.com/forum/showthread.php?t=299093

I've found quite a few other references to this technique on the net as well.

That said-- it's all anectedotal.

I'm very interested in your comments Gadget. The alternative seems to be at best to use a corrosive flush like Prestone Super Clean, or a worst, replace the radiator, hoses, and heater core. Definitly am looking for downsides here before doing this. I don't know if the condition of the cooling system can get any worse than it is right now, but I don't want to risk further damage of the new gaskets or anything. Seems that quite a few people have done this with satisfactory results.

And thanks for the suggestion Jake-- like you say, this would avoid cutting the hose-- those plastic T's don't look very durable.

toy283

To answer your first question, if the directions say to put it in the line running "from the firewall to the engine", it will be the cooler of the two. On my trucks, it is the one on the passenger side so I'd imagine it's the same for you. That said, I prefer to put it on the other one, before the heater control valve. By doing this, when you shut the valve, you force the water to flow backwards through the system which is the whole point of a "backflush". During times when the valve is open (which it needs to be at least part of the time), the water will flow whichever way is easiest which may or may not be backwards through the system.

Jake94

Years ago I use "Arm & Hammer" Washing Soda Not the same as Detergent. It worked well.

I have since switched to BG cooling system flush as recomended by my mechanic and the Toyota dealer.

Jake.

Sludge

You want to install the T on the hose that runs from the T-Stat to the firewall/heatercore. This way the T-Stat does not have to be open to flush the system. Thats how i have it install on my rig with no problems other than the location. I took off the skid place to access that area.

hpinson

Well, this went well.

I throughly mixed about 1/4 of a small box of Calgon with water, making sure to disolve well, drained the cooling system, poured the mixture into the radiator, and ran the engine for about 15 minutes with the heater on.

What came out was a nicely emulisfied mixture of oil, coolant and water. Rinsed, using the Prestone flush kit, with running cold water for about 15 minutes, with the engine running, and heater on full, drained, then repeated the process a second time.

After that, the water came out clear, and the inside of the radiator, from what I could see, looked much better.

Then I rinsed for about 45 minutes with clear water, engine running, heater on. The water started running clear after about 15 minutes, but felt soapy until about 20 minutes. Then I drained for about an hour, and refilled with one gallon of Toyota red coolant 50% and distilled water 50%. I've run for about a day now and the coolant looks very clean with no hint of oil. I may repeat this in a few months, in a few months, as the oil is probably stubborn. I'll most likely change the hoses then, as the oil eats at them.

I should say-- do this at your own risk-- I have no idea what the long-term consequences are, though I can't think of anything bad if you flush enough. The alternative in my case was a new radiator and heating core.

Water temp is now right where it should be.

betelnut

Sorry for awakening the dead thread, but this question wasn't clearly answered. This is a top result on Google, and lots of good info. Here're a few more tidbits.

Jake94 is right, the heater valve (3VZE), attached to the firewall above the LH cylinder head, has an arrow pointing toward the hose that goes thru the firewall.

According to the Prestone directions, you want the heater *inlet* hose, so that's the right one.

Before the valve, the hose curves around through a metal pipe. Before the pipe is a nice location to cut the hose and install the tee.

The garden hose attaches to the tee. I'm guessing the logic is that with the heater valve open, you're not really washing much junk into the heater core, since that path is pretty short. The water goes both through the core and backwards through the inlet pipe from the tee.

Instructions say to have both the radiator petcock and the radiator cap (with spillover attachment) open. Again I'm guessing the logic, there's very little debris that will be washed (at least with any force) through either radiator core or heater core, the most debris-sensitive parts of the coolant system.