Swapped radiator, etc. today. An interesting discovery.

[alp]

As I posted before the coolant temperature reading since I started monitoring it with my Scangauge II was 207 F sometimes climbing up to 215 F. . After reading this thread I have decided to replace the thermostat and I did it yeasterday. I have ordered new thermostat and gasket from Rockauto.com - Stant p/n 48118 and 25286 accordingly. Good quality stuff made in Japan. It took me about 2 hours to do the job done. Took my truck for a test drive after that. The temperature was between 188 and 190. Drove my truck to work this morning (50 miles mostly highway) - the temperature was 188 flat all the way. I am happy. Thanks a lot to Qyota for very useful information!
New radiator is next on my list.

 

[Qyota]

Awesome! That's great news. As an update, yesterday it was 84 degrees here, and the hottest my truck ever got was 193F. And once I got up some speed, it quickly came down to 186-188. That's how it should work!

 

[COShadow]

Hmm, was your old thermostat a factory toyota part? I replaced the entire cooling system within the last 2 years. 1st-- water pump. After a year, I replaced the radiator, hoses, cap, t-stat and coolant. Went from the 180s to now at 204-206. It was the same for 2 brand new toyota t-stats. I put the old t-stat back in and operating temps went back down. Then I put the new one back in and have been running it since at 204-206 F.

I wonder if Toyota has a bad batch of t-stats that people are buying?
Your new t-stat is aftermarket? What brand was your t-stat when you were running the higher temps?

 

[Qyota]

I'm not sure what brand came out, but I put a Stant model back in. Still working perfectly, staying mostly around 188F.

 

[alp]

Hmm, was your old thermostat a factory toyota part? I replaced the entire cooling system within the last 2 years. 1st-- water pump. After a year, I replaced the radiator, hoses, cap, t-stat and coolant. Went from the 180s to now at 204-206. It was the same for 2 brand new toyota t-stats. I put the old t-stat back in and operating temps went back down. Then I put the new one back in and have been running it since at 204-206 F.

I wonder if Toyota has a bad batch of t-stats that people are buying?
Your new t-stat is aftermarket? What brand was your t-stat when you were running the higher temps?

I will check the old thermostat brand/nameplate tonight. It was there for about two yeras before I replaced it with the Stant's one. I installed it together with a new pump and t-belt right after I bought my truck. At that time I installed it with the jiggle valve at 12 o'clock. It appears that it is upside down from recommended position. Could that contribute to the elevated coolant temperature that I had before? Maybe. This time I installed the t-stat with the jiggle valve at 6 o'clock, as recommended. Now it is 188 - 190 deg. F all the time... well, untill recently after I was caught in the traffic jam. It climbed to 215 deg. F - Oh boy! So, last week I replaced the fan coupling and that solved the problem.

 

[Satter]

Satter, I have had an external cooler for over a year now, so this was not to prevent the milkshake. However, I did not know the age of the radiator, and they are cheap enough to just replace and forget about for another decade.

Thanks for the info, chief.



The other day I went to the dealership to get my oil change. (Decided not to go with synthic btw). The guy who's my service advisor has been at Don McGill Toyota since I bought my 3G4R back in Oct 97. He's been very honest with me, saving me hundreds of $$$ throughout the time I've owned my vehicle. I asked him straight up "Should I replace my radiator to avoid the engine coolant mixing with the tranny coolant?" He told me that the radiator cooling both the engine and tranny at the same time is a used in many vehicle makes. Not just Toyotas. Something I didn't know. He told me it's rare, but mixing of coolants does happen. He told me swapping out the radiator wouldn't be a big deal at all. $500 parts & labor. But, he said I shouldn't worry about it.

I'm a big believer in "if it's not broken then don't fix it". But, I'm also an even bigger believer in protective maintence. God willing I'll keep this truck until I die. I just wanna do what's best. But, I don't want to do something I really don't need to do. Like change from Dino to syntheic oil. Just don't know.

 

[Qyota]

Don't pay $500 to have them replace your radiator. You can get a new one for $125, and put it in yourself in an hour or less. Add in the price of new coolant and some distilled water ($25 total), and you're off and running.

 

[alp]

Don't pay $500 to have them replace your radiator. You can get a new one for $125, and put it in yourself in an hour or less. Add in the price of new coolant and some distilled water ($25 total), and you're off and running.

Totally agree with Qyota. Do it yourself and sleep well.

 

[Nelsonmd]

Don't pay $500 to have them replace your radiator. You can get a new one for $125, and put it in yourself in an hour or less. Add in the price of new coolant and some distilled water ($25 total), and you're off and running.

Yeah, just get a B&M tranny cooler, $60 and the problem is solved for life. Takes a couple hours or less.

Sure the percentages on the milkshake may be relatively low (in the single digits, or sub 1%), but it is likely to ruin your tranny if it happens (not to mention strand you), and it's only $60 to prevent. Worth it to me.

 

[COShadow]

Well, I flipped the thermostat that was in my 4runner so the jiggle valve was at 6 o-clock instead of 12 o-clock (FSM says install it at 6 o-clock). Indeed, my running temps went from 202-206 down to 190-193. Should be smooth sailing now.

Thanks 4runnerers

 

[quicksilvr]

Very interesting that the jiggle valve position makes that much temperature difference. But great to know.


What's the best method to change coolant at home? My truck is currently filled completely with Prestone "mix-with-any" coolant. I have a whole case of Zerex Asian though...and I want to completely switch. How do you go about getting all the old stuff out, and then getting the new stuff in, without diluting it? If I flush with water, then there's going to be too much water in the new Zerex (it's premixed). Any ideas?

 

[RC57]

For the coolant, I mixed 50/50 Toyota super long lasting with distilled water, and used the Lisle coolant filler funnel (I tell ya, that thing is WELL worth the $25!). The system took 2 gallons of the mix, and left me with just enough to get the reservoir up to the proper level.

Super Long Life coolant is already premixed. If that's what you used, it's probably too dilute now to handle Wisconsin winters.

Toyota Long Life coolant is concentrated and should be diluted 50/50.

 

[COShadow]

Very interesting that the jiggle valve position makes that much temperature difference. But great to know.


What's the best method to change coolant at home? My truck is currently filled completely with Prestone "mix-with-any" coolant. I have a whole case of Zerex Asian though...and I want to completely switch. How do you go about getting all the old stuff out, and then getting the new stuff in, without diluting it? If I flush with water, then there's going to be too much water in the new Zerex (it's premixed). Any ideas?

Huh, I'm not sure what to tell you, I'm not an "expert". I would say flush with water and get as much out after that. If you get most of the water out before putting your new stuff in, you should be fine.

 

[Qyota]

Super Long Life coolant is already premixed. If that's what you used, it's probably too dilute now to handle Wisconsin winters.

Toyota Long Life coolant is concentrated and should be diluted 50/50.

Mixed my terms. I used the concentrated stuff.