How to flush the Cooling System prior to Radiator change?

[Brett]

With the other discussion about Radiator types I think it would be a good idea to pool the forum knowledge on how to correctly flush the cooling system prior to installing your nice shiny new radiator?

I'm also about to replace my radiator, it's only 2 or 3 years old but it's leaking from the join where the plastic tank sits. It was fitted by the previous owner & when I bought it was filled with green coolant. When I bought the truck I tried to flush the system to replace the green coolant with Toyota red, but unfortunately couldn't locate the block drain plug So I just flushed as best I could & refilled with fresh green coolant & distilled water.

I suspect it's the green coolant thats caused the problems.

Anyway, I've just ordered a new radiator (genuine parts) hoses, clips & red coolant & am planning to swap them next week end. I have now, (I think ) correctly located the block drain plug.

Prior to doing the job has anyone got a good method of thoroughly flushing the cooling system? by that I mean the rad, block & both heater matrixes. Also is it worth adding any flushing chemicals?

Agrimach do a radiator flush kit which I'm thinking of buying.

http://www.agriemach.com/product_info.php?cPath=60&products_id=859

So please if anyone's done this before & has any tips please post them here.

 

[ajnabi]

Re: How to flush the Cooling System prior to Radiator change

Is this the stop cock / drain plug (large bolt just right off bottom centre) on the engine block of the 1HD-FT?

IQ

 

[Brett]

Re: How to flush the Cooling System prior to Radiator change

That's the one I hope it is, it's a brass bolt with a smaller bolt screwed into it. I'm assuming you undo the smaller bolt leaving the large one in situ.

 

[ajnabi]

Re: How to flush the Cooling System prior to Radiator change

Here is a clearer picture of the engine block coolant drain plug, but this time on the 1HD-T.

IQ

 

[Andrew Prince]

Re: How to flush the Cooling System prior to Radiator change

I had a look at Harry/Cantako's website (he's based on another forum Pity we don't have him join us as he seems very knowledgeable ) Anyway, he had a write-up on his own website about flushing and replacing the rad that might be useful.

EDIT: Brett, are you replacing the thermostat while you're at it or leaving the old one? I helped replace Matt Wright's rad on his 1HD-T, so my experience is based on that. (Comparing with mine at the time, the HD-FT looks a bit trickier to do the way hoses and alternator sit when it comes to accessing the lower hose and stat). We could not find the drain cock on the engine so we just let the coolant drain from the lower hose. We removed the grill and both batteries + battery trays to get at the rad and remove it. I guess you could do it with most bits left in place but it makes everything much more accessible removing it.

 

[Chris]

Re: How to flush the Cooling System prior to Radiator change

Err, I have found the drain cock on the 1HD-T and posted it a while back. I know it's the drain cock, because a drained it. But that was not it on the oil filter housing. It's on the side of the block between the IP and the oil filter. It's pretty small and a bit tricky to get to but it does drain the block.

Basically it a small brass fitting screwed into the block with another threaded plug set in the middle. I removed the lot as the tap wouldn't turn and the outer body would.

Chris

 

[ajnabi]

Re: How to flush the Cooling System prior to Radiator change

Hi Chris, I've got the following 2 links:

http://www.landcruiserclub.net/forum/viewtopic.php?f=15&t=7942
&
http://www.landcruiserclub.net/forum/viewtopic.php?f=15&t=8486

...none with pics though.

Also a link on lcool:

http://www.lcool.org/forum/viewtopic.php?t=7755&sid=25c95d55bdaf7d1b603542278cd44ea2

... the link to the picture in this is duff.

IQ

 

[Chris]

Re: How to flush the Cooling System prior to Radiator change

Yep, the first post is the one. I wrote

"An old thread I know. But I found the drain cock on my 12v. I wanted to make sure that I got all the coolant out of the system as I had put a flush in there, so I set about looking for it. Man it's tricky to find, but it's there, halfway along the engine between the oil filter and injector pump. It's a hexagonal fitting about an inch long needing a 14mm socket for the outside and a 10 mm socket for the tap in the end. I tried to unscrew the tap, but it just wound the whole fitting out of the engine. All cleaned up now ready for next time. You need at least 6 inches of extension on a socket to reach through all of the fuel lines etc. You can see it if you look down through the gaps in the inlet manifold. Tricky little sucker, but it did let a lot of water out. Got full ten litres in on the refill."

Difficult to take pic. It's pretty buried down there. You need a small socket set and extensions to get to it.

In terms of flushing, I drain and refilled with plain water, run and drain again. I stuck an engine flush product in too, then drained and filled again with water to get any residue of the flush out of it. I took the rad off and back flushed with a hose pipe. Looking in the bucket, I did get quite a bit of grunge out of there, but then my truck had not been cared for.

Chris

 

[ajnabi]

Re: How to flush the Cooling System prior to Radiator change

Here is another 1HD-T ... is this more like it?

IQ

 

[Chris]

Re: How to flush the Cooling System prior to Radiator change

That's it fella!

Of course when the engine is built up, it's not quite so accessible.

Good pic.

Chris

 

[Bat21]

Re: How to flush the Cooling System prior to Radiator change

That's it fella!

Of course when the engine is built up, it's not quite so accessible.

Good pic.

Chris

Nooooo it aint

I've just been out to the garage and took a photo of my old block, here's where mine is on my 1992 1HD-T

 

[ajnabi]

Re: How to flush the Cooling System prior to Radiator change

Paul,

I think you're both right!

I have a feeling some 1HD-T blocks had them on the right of the oil filter and some on the left as above.

However I think all 1HD-FT blocks have them on the left!

Correct me if I'm wrong.

IQ

 

[ajnabi]

Re: How to flush the Cooling System prior to Radiator change

Another view, no wonder it's hard to locate!

 

[Chris]

Re: How to flush the Cooling System prior to Radiator change

OK, to be clear - that IS the fitting. That is what I was referring to. Mine is exactly the same as Paul's, in terms of location. But on the pic of the block that you showed, that is the drain cock. I didn't look at the block very carefully in the pic I have to admit. I actually just took it to be a block like mine that wasn't built up taken from a funny angle.

I looked for ages but it was only with a bright LED torch that I finally saw it.

Chris

 

[Bat21]

Re: How to flush the Cooling System prior to Radiator change

Another view, no wonder it's hard to locate!

The drain cock on mine is located behind the spaghetti of injector pipes which are to the left of the oil filter.

I think the other one you have shown has a sender unit screwed into it on my block.

Oh, and I think your block may be cracked as I can see one of your pistons... No5 I think

 

[ajnabi]

Re: How to flush the Cooling System prior to Radiator change

LoL ... yeh you would know!
How's it running since the rebuild?

Thanks for the picture - makes it much clearer and a good reference for others.

IQ

 

[Justin_Elliott]

Re: How to flush the Cooling System prior to Radiator change

Now if you were to have blue coolant in your truck... and wanted to flush in order to refill with Red would you follow the same procedure? I understand the two don't mix... would you just add more flushes or use a specific rad flush...

Is it advisable to switch it back??

 

[Bat21]

Re: How to flush the Cooling System prior to Radiator change

LoL ... yeh you would know!
How's it running since the rebuild?

My motor has done about 750 miles now since the rebuild and is running fine.

I used running in oil for the first 500 miles and now she is on Morris's semi-synth and doesn't appear to be using a drop

 

[Brett]

Re: How to flush the Cooling System prior to Radiator change

Thanks for all the replies so far chaps.

From Pauls photo I've been out & had another look & still can't find the drain cock

I'm beginning to wonder if it's actually superseded on the 1HD-FT Blocks?

If you check the parts catalogue it's shown here.... which is the same as Pauls photo.

Looking at another diagram the part the drain is mounted in is the Oil cooler cover P/No 15721-17020.

 

[Bat21]

Re: How to flush the Cooling System prior to Radiator change

Looking at another diagram the part the drain is mounted in is the Oil cooler cover P/No 15721-17020.

Correct, it is mounted on the oil cooler cover... certainly is on mine for sure

It is very difficult to see as it is behind all the fuel pipes.

Looking at your Toyodiy shot, it is possible that yours is further back as mentioned earlier