Supercharged 5VZFE and cooling

[Arclight]

Hi all,

My 97 T100 has a 5VZFE and the TRD Supercharger installed. It's the black (2nd Gen) model. Everything works great for the most part. The one issue I have is going up long grades in the Summer. The temperature normally runs 182-195, but it will rapidly get over 220F on long climbs in the Summer. This is according to my OBDII information, and backed up by the idiot gauge beginning a climb towards the red. From my observations, the red line on the gauge is probably around 230F.

My engine was rebuilt professionally about 30K ago. It has new hoses, belts and water pump and a new Koyorad 1.25" core Aluminum radiator. I'm running a 50/50 mixture of green Prestone coolant. The A340 automatic is using both the radiator and an external transmission cooler. I also replaced the fluid in the fan clutch with 10,000CST silicone oil. It has new sparkplugs and a fairly fresh catalytic converter and muffler. It has never thrown any codes.

The problem is helped somewhat if I turn off overdrive and keep the boost off, but it still happens. I usually end up turning off the A/C and keeping the speed down to 40-55, depending on the grade. When I do this, it keeps the temperature from going over 220, but it obviously isn't fun.

Does anyone else have experience with this? I can run full-throttle up grades when it's cold outside, but really have to baby it when it's 90+ degrees out.

Any thoughts?

Arclight

 

[plainjaneFJC]

Can you get a radiator with more surface capacity?

 

[(none)]

are you sure your fan is working properly? At those temps, that thing should be howling. I took the mechanical fan apart on my LC80 and replaced the fluid, it never worked correctly again. I'd try a new clutch for the fan first to see if that helps anything.

 

[volkinator]

With the S/C did you put in a lower rated Thermostat? I think the 5VZ comes standard with a 175* but I put in a 170* with mine. granted we don't have a lot of mountains, but even on the hot & humid days mine never gets above 195...

 

[plainjaneFJC]

With the S/C did you put in a lower rated Thermostat? I think the 5VZ comes standard with a 175* but I put in a 170* with mine. granted we don't have a lot of mountains, but even on the hot & humid days mine never gets above 195...

I don't think it would make a difference under load up a hill he is already above those temp points anyways. I think it's either the fan as someone suggested above or it just needs more cooling capacity.

 

[cruiseroutfit]

I combated a little heat issues with my SC'd 2004 5VZ (Tacoma). Highest I ever saw was 222? as shown by my scangauge. I installed a TRD thermostat and clocked it with the correct wiggle valve orientation. That seemed to do the trick for me, I don't recall ever seeing more than 210 after that on a long grade and that was pushing hard.

 

[Arclight]

I combated a little heat issues with my SC'd 2004 5VZ (Tacoma). Highest I ever saw was 222? as shown by my scangauge. I installed a TRD thermostat and clocked it with the correct wiggle valve orientation. That seemed to do the trick for me, I don't recall ever seeing more than 210 after that on a long grade and that was pushing hard.

I have a new Toyota thermostat and I clocked it the right way, according to forum lore anyway, Is the TRD T-stat any different? More flow?

Arclight

 

[ExPo4Runner]

It has a lower trigger point from what I recall, not sure about the flow. I also recommend flushing and going back to Toyota red when trying to fix these problems.

 

[Milo902]

I have a 96 4-Runner w/ the 1st gen (grey) supercharger, about 35kmiles on the install, 285k on the truck, 5-speed w/ the URD 7th injector. I haven't check through a scan gauge, but my idiot gauge never moves from center, even beating on it up to the Eisenhower filled with gear, people and dogs. Now I'm curious, I'll have to see what my OBDII app says next time I'm in the mountains. Sorry no help, just another data point.

 

[Mattm94]

The problem is helped somewhat if I turn off overdrive and keep the boost off, but it still happens. I usually end up turning off the A/C and keeping the speed down to 40-55, depending on the grade. When I do this, it keeps the temperature from going over 220, but it obviously isn't fun.

If you don't turn off overdrive on that auto while pulling grades, that's part of where the heat is coming from. The overdrive function doesn't allow torque converter lockup and creates a HUGE amount of heat when it's working. Turn if off every time you pull a grade, or you'll be rebuilding or replacing that transmission in short order. A temp gauge mounted inline on your cooling line is very enlightening here. The cooling line comes right out of the converter, and is typically the hottest point in the fluid stream. Pulling a grade with o/d on, and inline temps of 230-240, turned off, they will go down to 190 almost immediately. A full flush and synthetic fluid helps. A modified valve body to reduce the "comfort slip" in the shifts is better.

The advice already given is spot on with the radiator and fan clutch. Get the greenish blue one from Toyota for a 5vz, no aftermarket stuff. 2000s Taco, tell them it has the towing options, or a limited 4Runner from the same vintage. Can't explain why, but I've NEVER had success taking one apart and replacing the goo inside. I have no experience with Koyorad, so can't comment on that.

Watch your scan gauge and make sure your injectors and pump are keeping up. If they're not, you should be seeing it lean out at upper RPMs and loads. Running under load with a lean condition isn't going to help those pistons last. Solutions for this are many, and well documented on several sites. A supercharger isn't really purely "Bolt On" for these motors.

If all else fails, run a slightly weaker coolant mix if you can, and get some "water wetter".

 

[Mattm94]

Well, fortunately for me, I'm not forced to guess or ask questions about this particular scenario. You'll notice I specifically stated I have no experience with Koyorad so refrained from comment on that, since I'd have no idea what I'm talking about. I've had and driven more than a few Toyotas. And it's a small sample, but I've owned, driven, and towed with 4 of them with the engine and tranny combination he's asking about, in what's most definitely considered extreme heat and grades.

In his original post, he stated that the tranny cooler line was still routed through the bottom of the radiator. So yeah, 280+* fluid from a heavily slipping converter, turned by a supercharged 3.4, running through the bottom of the radiator, could contribute to some increased coolant temps. I'm also NOT guessing about this.

 

[Mattm94]

I think you misread my post. It's easy to know when the O/D is off... there's a light in the dash, conveniently labelled "O/D OFF".

"If you don't turn off overdrive on that auto while pulling grades, that's part of where the heat is coming from. The overdrive function doesn't allow torque converter lockup and creates a HUGE amount of heat when it's working. Turn if off every time you pull a grade, or you'll be rebuilding or replacing that transmission in short order."

 

[rexwang]

do you have an idea of your EGTs or a/f ratio when youre climbing?

you might be running a tad lean. running lean makes the EGTs shoot up, and thus a warmer running engine. just wondering. something else to consider.

 

[99Yota]

Hope this gets fixed soon- nothing more sucky than having to climb grades watching the temp gauge.

Some low-tech troubleshooting:
- Radiator cap- does it have the small plunger (circled red) intact? If not, radiator may not be developing pressure and vehicle can run hot.

- Themostat - doubtful but it could be defective. Any chance it isn't opening all the way?

After removing the radiator cap on a cold engine, try starting it and see if at about the 2 or 3 minute mark, you see added flow and hear a slight drop in RPMs. If it behaves normally, I'd consider pulling the thermostat and try running it open and see if the temp stays any lower climbing a long grade.

You could also try running a compression test to confirm uniform compression just to rule out a cracked cylinder head.

 

[Arclight]

do you have an idea of your EGTs or a/f ratio when youre climbing?

you might be running a tad lean. running lean makes the EGTs shoot up, and thus a warmer running engine. just wondering. something else to consider.

I have a Scangauge II installed and the X-Code for "AF1" on the Toyota. It appears to be a reading from 0-99, that starts out high on a cold start. Can someone give me an idea of how to interpret the air/fuel number?

Arclight