Running Hotter after new radiator and other parts (1 Viewer)

[SanDiegoCruiser]

I’ve done a ton of searching and even taken my rig back to my mechanic twice regarding this issue. 99 100 with 150K miles. Had mechanic replace radiator with Denso OEM for preventative maintenance about 1 year ago. I immediately noticed the rig running 10 -15 degrees hotter after this. Took it back to mechanic who suggested I replace upper lower hoses, T-Stat and fan clutch.

After this second round of work was done it ran a little cooler. Rig sat in garage during pandemic and didn’t get driven much. Took it out on a trip a few weeks ago. 90 degrees out and climbing up a minor grade had the scan gauge reading of 215 degrees!!

So I visited mechanic again and I suggested the radiator was defective. He doesn’t think so. I’ve double checked the coolant level, burped for air pockets etc. What am I missing here??

 

[TheForger]

Have you flushed it recently? I know you said you burped it but it sounds like you may still have some air in there.

 

[MongooseGA]

Burp it again. It can be a process.

 

[aljollano]

^^x2

 

[Trunk Monkey]

There's a radiator fill tool you can get, dunno if maybe the parts places rent it - it pulls vacuum on the entire coolant system, collapses the hoses and all, then you open the valve and it sucks coolant in from a big container of it. Guarantee no air pockets.

 

[SanDiegoCruiser]

The way I’m burping it is removing radiator cap, turning on front & rear heat, starting engine and letting it get up to temp at idle. Is this the correct procedure?

 

[MongooseGA]

Getting the nose up a little bit can help. I use rhino ramps.


It's taken me 2-3 times before to get it fully burped.

 

[TheForger]

^ Yeah I park it nose up on my driveway. That puts the center of the front hub at least a foot above the center of the rear hub

 

[JunkCrzr89]

Getting the nose up a little bit can help. I use rhino ramps.


It's taken me 2-3 times before to get it fully burped.

^ Yeah I park it nose up on my driveway. That puts the center of the front hub at least a foot above the center of the rear hub

#MeToo

 

[SanDiegoCruiser]

Well I tried to burp again today In driveway and still no change. Still runs 200 F going up a local small grade when it’s 75 ambient temp.

 

[TheForger]

Did you go OEM on the t-stat or aftermarket? Some t-stat’s open at different temps than others

 

[SanDiegoCruiser]

Did you go OEM on the t-stat or aftermarket? Some t-stat’s open at different temps than others

OEM t-stat

 

[TLCOVERLAND]

OEM t-stat

I know it has been a few months, but when burping the radiator you have to keep the RPM around 2500 for 10-15 minutes to get all the air out.

 

[94SRUNNER]

I know it has been a few months, but when burping the radiator you have to keep the RPM around 2500 for 10-15 minutes to get all the air out.

No I don't believe you do. I have never had to do this when burping the air from a coolant system. I have always allowed the engine to idle until up to operating temperature with the front and rear heat on high, the front end slightly elevated, the radiator cap off, and that takes care of it.

 

[FxFormat]

This system should be self bleeding anyways, whatever air is trapped will work its way through the highest part of the cooling system, which is the cap, then it'll burp out to the reservoir and will draw it back in when it cools. I've replaced tons of radiators and after a couple heat cycles the reservoir will remain constant with fluid level.

 

[SHIfTHEAD]

FWIW, I worked on my buddy's 4runner where it was running hot so we replaced the Tstat, all hoses, water pump and radiator. Issue was slightly different after it was all together. He bled it again, burped, refilled and was taking it all apart again when he noticed some Styrofoam bits floating out of the radiator. Took it back out and completely flushed it again and got all the trash out of it the factory left in there, fixing the issue.

 

[OwnerCS]

Does the 2UZ have a t-stat jiggle valve that is "clock position" sensitive like the 5VZ?

 

[Ayune]

Does the 2UZ have a t-stat jiggle valve that is "clock position" sensitive like the 5VZ?

Yup, the jiggle valve goes up.

 

[OwnerCS]

Yup, the jiggle valve goes up.

And if the jiggle valve is pointing down, I take it the engine runs hotter than normal for no apparent reason?

 

[flintknapper]

No I don't believe you do. I have never had to do this when burping the air from a coolant system. I have always allowed the engine to idle until up to operating temperature with the front and rear heat on high, the front end slightly elevated, the radiator cap off, and that takes care of it.

^^^^

Same procedure for me....except I use a filling funnel and let the radiator burp and fill itself at the same time. Never had an air pocket issue this way.