HOT!!! I'm thinking airlock?

[Bahamasair]

Im going to bet your head is cracked. Does the top radiator hose get hard as soon as you start the truck? I had one with the exact same symptoms and it was the head I'm afraid. I have one now that almost has the same symptoms, it's not bad enough to push the coolant into the expansion tank but will loose coolant over a couple of weeks and it's always pressurized when I open the rad cap.

[Sylux]

Just refilled the rad from the expansion and noted a few things:

1: This time there was no pressure left in the system (top hose was soft and cap sucked in nothing on opening).

2: Coolant is as new (no contaminates)

3: There is zero coolant loss (no top up needed)

I also now realise how the cap works on letting coolant back in from the expansion tank. If I'd left it full (expansion) and started her up...I'm guessing that's the point it would have sucked back in? I'll leave the expansion tank full, tomorrow, and see if it does the job.

[Sylux]

Does the top radiator hose get hard as soon as you start the truck?

Nope...stays soft

[charvell]

Just refilled the rad from the expansion and noted a few things:

1: This time there was no pressure left in the system (top hose was soft and cap sucked in nothing on opening).

2: Coolant is as new (no contaminates)

3: There is zero coolant loss (no top up needed)

I also now realise how the cap works on letting coolant back in from the expansion tank. If I'd left it full (expansion) and started her up...I'm guessing that's the point it would have sucked back in? I'll leave the expansion tank full, tomorrow, and see if it does the job.

The rad cap will let the coolant back as the engine cools it has nothing to do with the engine running. As the engine gets hot the cap opens and allows the pressure and coolant into the expansion bottle.

Why do you think you have an air lock? Have you just flushed it and changed the coolant?

I would get get the head checked.

[Sylux]

There's no sign of the head going...that's why I'm thinking along the lines of an airlock.

I can't get my head around why the coolant isn't going back into the system from the expansion tank.

Before I fixed the exhaust and deleted the rear heaters it was staying with pressure throughout the night (which would explain it). But now the pressure is going...it's not pulling it back in.

I'm just confused with this symptom as I no longer have over-heating.

[woodwarm]

Is the pipe( rad cap to expansion bottle) split/ leaking ?

Replace the Toyota pipe clips with jubilee clips.

I had this problem with mine

[Sylux]

Hmmm, think I'll remove them and check. I've only checked for blocks. Thanks for reminding me

[Dobbslc]

If you have a leak even a tiny one ie a loose or split hose OR a crack in the head leading into a coolant passage you will loose the vacuum created as the coolant cools and contracts, this in turn will mean the excess coolant in the expansion tank won't be drawn back into the rad.

You have a leak or a buggered head I would say.
Re the lack of any signs of a cracked head mine ran perfectly for 18 months except for using a bit of coolant. It had 20 cracks in total!

[Sylux]

I must be the only person to be happy to see a leak puddle on my drive...but there was one today

Looks like the radiator is leaking. I'm investigating the leak, now...but it seems to be from the top seam.

This could explain a lot. Not losing coolant previously could be because the crack/gap may have been just allowing air in or out at certain times. Or any slow leak had gathered elsewhere and evaporated. Plus I could have presumed it was me spilling a little bit of coolant on transfer from expansion tank to rad.

It's still holding the coolant but it looks like a slow leak has developed.

Fingers crossed this is my issue. And fingers crossed the 2 year warranty holds up (only bought last April)

[shokenore]

Fingers crossed its just the rad, and they honour your warranty.
Is it a all metal rad ?
Mine started leaking along the top seam
I pulled it out and cleaned all the old solder out of the top seam and resoldered it, and built up the solder a bit.
Blow torch, plumbers solder and bit of time.
Lick of paint and its better than new.
Hopefully though they will send you a replacement.

[Sylux]

I'll see what the seller says...but I'm not afraid to get my plumbers solder on the bad boy

Might do it in situ!

It's definitely the top seal. Coming from near the cap area. I'd thought it was just me spilling a bit. But drying it off and watching it reappear has shown the way.

[shokenore]

Yep looks very very similar to mine pre repair.
I had mine out as I took off the end plate/mounting bracket so I could solder all the way around from front to back, plus I didn't want to risk melting the battery cable insulation.
I gave it a good flush too and deleted the ATF hose connections to boot.

[Sylux]

How did you delete the ATF connections? Utterly pointless for manual owners

[andyverran]

Isn't there a manual rad?

[Sylux]

Probably...but it's likely in Australia and cost a fortune.

I love that all alu one that's out there. But it's pricey. Shipping £70+