1uz in 88 4runner overheating issue

[Shepard_999]

Hi all. I have a 1uz in my runner and I can't seen to get the cooling side of thing right. I have an oversize full alloy radiator out of a supra in it running a custom made shroud with a 14" thermo fan on the inside, EL falcon fans on the outside pushing. I have removed the double bypass side of the thermostat housing and running a thermostat with the guts cut out so the radiator is getting full flow. When sitting idle the temp just keeps creeping up. Any suggestions. Cheers.

 

[gloverman]

So you have ensured that the bypass circuit is completely closed?

 

[Shepard_999]

Yeah. I pulled the housing off and welded a plate over the bypass port engine side so i can still use the factory thermostat.

 

[gloverman]

Does it make a difference when you turn the heater onto hot with the fan going. My present Surf is running a Stock radiator with trans oil cooler in front of it and the tiny little factory A/c fan that the diesel surfs run. Normal driving no issues with heat and it would idle all day without a problem. And its been a hot year over here this year. Even 4x4ing a steady pace its fine. It only has an issue if I am pushing it hard offroad. One day ill get around to fitting the extra fan which is presently sitting in the boot.
I never recommend removing the thermostat , even with the bypass circuit blanked.
Have you tested how much air flow your fans have? is it going through the radiator or around the radiator?
Any other restrictions in the front of the vehicle?? bullbars , winch etc
Does the thermostat hose go the top of the radiator or the bottom?

 

[Shepard_999]

Im playing around with the outter fan at the moment and have just cabletied a big one i had to the outside and it seems to be holding at 80 at idle. i'm just testing if it will work or not. the shroud on the inside i made but the fan is a peice of crap and im currently waiting on my daives craig to arrive. just hope it will fit. i normally don't run without a thermostat but untill i get it right i needed to make sure that it wasn't my problem. turning on the heater didn't make a difference. once the wife gets home i'll take it for a drive without the front end on and see how it goes.

 

[Shepard_999]

Is there an engine driven fan that bolts straight to the 1uz. If so would I be better off with that rather than electric fans.

 

[gloverman]

There is but I dont think you will have room to fit it into a surf.

 

[Shepard_999]

Do you happen to know how much room id need?

 

[gloverman]

I dont sorry. I dont think I have one laying around anywhere either. I did have a viscious fan engine come in before christmas and I sold the idler unit which the fan attaches to pretty much straight away as we use them without the fan as an idler when running air con. I dont know what happened to the fan or if it was even on the engine.

 

[Shepard_999]

No worries. Do you happen to know if the 2uz one out of a 100 series landcruiser will fit on the 1uz. Sorry to be a pain with all these questions but its doing my head in.

 

[BlackUZZ31]

checked ignition timing?

have you done a cam belt on it - checked cam timing?

checked fuel pressure and mixtures with a wideband o2?

 

[Shepard_999]

Sorry black i didn't realise you commented. yeah i have checked and double checked everything. i have opted to putting a different radiator in the old girl. i'm putting a au falcon radiator in it with the factory au fans. i have opted for a falcon radiator because it has no cap on the top so it can go right under the support. i'll run a remote header tank up high on the fire wall somewhere. I have made the support panel removable and it also is the locator for the radiator.

 

[dar_sbb]

Hey shepard,

how did u go with the falcon radiator?

 

[samsdad]

I find this funny in a way so please don't take offence.

I have a Toyota Surf much the same as Dazzas one. It has a 1991 UZZ31 Soarer engine with tickled ECU, Green top injectors, Custom made extractors, That Dellows crap between the engine and box (but that is nothing to do with this thread) and the cooling system? Bog stock standard Diesel Surf radiator albeit with a filler neck fitted to the top tank. Spal 16 inch fan which due to my inherent laziness runs when the fuel pump does. Does it get hot? No. Does it overheat off road? No. Does it overheat with the A/C on during Perths hot days? No

What did I do? I kept it simple, Run a good thermostat, genuine Toyota coolant or if not available its equivalent AND I increased the oil capacity of the sump. My conversions are generally IFS and rather than just notch the sump I extend it so I end up with a total oil capacity with filter change of 10.5 litres. Air flow at speed is also important. 4 years ago I fitted a nice big bull bar that I got off a write off that I'd purchased for spares for my then professional operation. This also had some rather nice expensive driving lights on it so on the whole lot went. Well at a speed which I won't disclose or with a heavily loaded trailer on she did start to get a little warmer than what I was comfortable with so out with the hole saw and a few holes in the afore mentioned bar were cut, end of problem. Well she's been like this for 5 years and she did have a cooling problem yesterday when I drove her for the first time in 3 months (work in the mines, have a company car) Well the water pump shat itself due to lack of use...Grrr.. But it was an absolute pleasure to drive her again as I'd forgotten just how big the balls were

 

[ethann]

I've got a factory viscous fan if needed, newcastle area.

 

[dar_sbb]

simon, i have also gone the good ole 16in spal thermo. Good thing was i have never had cooling issues even off road (never been beach driving). Noise was my biggest issue.

 

[Shepard_999]

Hey I haven't checked this for awhile and thanks for all your comments. The falcon radiator is in and is working like a dream. It just fitted between the body mounts and every time I drive it now I dont even need fans running. They run off a 3 way rocker switch on the dash which is constantly on, off or auto (on at 95 and off at 85). I had to put the radiator in upside down and get the output modified to miss the power steering box. I also had to get a header tank which is aluminum and mounted up on the firewall. The radiator is also aluminum. I have had it on the beach and had no dramas.

I didnt do the conversion so it has been a bit touch and go. I want to pull the sump off and up the oil capacity a bit. The front apron was already cut to fit a different radiator so I thought id do it properly.

I'll upload some pictures of it fitted up.

 

[dar_sbb]

good work mate.

would love to see some pics