95 Series 3ltTD cooling issues

[Snoopy22 Member Find all posts View Profile Close Snoopy22]

Hi Prado gurus.

Ive been reading some threads relating to cooling issues with the 1KZ engine.

I still have an issue with my rig and I'm getting frustrated with my mechanic after spending thousands of $ trying to rectify the issue.
Over the last three months I have replaced the head, the radiator, two radiator caps, the thermostat and viscous fan oil. After all of that I still get my coolant bottle filling up to the top and when I take the radiator cap of when its cold there is no visible fluid covering the core.
The issue doesn't seem to happen around town only after I've done some freeway driving or pulling up hills.

Any thoughts, whats left to check?

[scottkz Senior Member Find all posts View Profile Close scottkz]

Water pump might be failing... Current shape hilux fit and the better
It could be that the impeller isn't very tight on the shaft so high speeds it slips

[Snoopy22 Member Find all posts View Profile Close Snoopy22]

Any way of testing this?

[scottkz Senior Member Find all posts View Profile Close scottkz]

Not really Iv seen it on a lantra a while back... Mechanics diagnosed as a blown head but was the water pump slipping
If you do a head on a 1KZ or any motor for that matter you should always change the pump and thermostat , was the water pump replaced with the head ? Or is it still the old one

[Snoopy22 Member Find all posts View Profile Close Snoopy22]

old one :cry:

[scottkz Senior Member Find all posts View Profile Close scottkz]

Bummer then ! There pretty easy to replace if your mechanically minded , if you get it done make sure the timing belt and tensioner were replaced with the head.... If they weren't I wouldn't be going to that mechanic again who replaced it

[Snoopy22 Member Find all posts View Profile Close Snoopy22]

I'm not really mechanically minded, why should the timing belt and tensioner also be replaced. Note had the belt replaced about 10K ago as part of regular servicing

[scottkz Senior Member Find all posts View Profile Close scottkz]

Belt every 100 with tensioner if that tensioner bearing fails or the belt slips or fails it an be fatal for pistons and head
If it was done 10k ago that's good

[grub Lurker Find all posts View Profile Close grub]

hey buddy, did you get this sorted? my 2000 auto GXL is doing the same thing. radiator top tank had a split and was 30% blocked so I replaced it. still pumping coolant into the overflow bottle but it doesn't draw it back. pressure test didn't show anything.

[scottkz Senior Member Find all posts View Profile Close scottkz]

Radiator cap

[Steve M Addicted PP Member Find all posts View Profile Close Steve M]

I personally think it's still the head. It pressurising the system. Brand new head I presume ?? Did he show you the old head off it for proof he changed it ?? Pressure test won't show up a cracked head and even the gas test they do if only a hairline crack and a tiny one at that and needs to be tested when hot as mine was, halfway down the freeway I pulled up and did the dye test on mine before it showed up. Mine was exactly the same as yours. I could drive round town all day even running aircon and gauge wouldn't move and all fluids normal level. Get it out on the freeway where she was working at higher speeds eg110 and could guarantee if I pulled up and checked the over flow bottle she was full and spewing out the little black overflow hose dripping over the ground. The crack in the head was so small would only open up when she was working harder. Couldn't even be seen under X-ray. Cost me 4k for a new good quality head supply n fit. Those cheep Chinese shit you see on eBay for $800 will last you 5 minutes and no point buying a genuine Toyota one cause they never changed or superseded the part number on the head meaning same shit head from when they first made them..... My bet the head is still not right, OR the head gasket wasn't installed correctly or damaged but I doubt it.... I did the same as you, new cap, thermostat, viscous coupling, and I pulled the radiator out and had it riddled etc and was still like new from the report. I sold mind after I had the head done but still going strong today.. (I know the owner).... Cheers Steve