Now that summer is upon us, I'm preparing to overhaul the cooling system.
Since getting a Scangauge a few weeks ago, I've noticed that my cooling system is bordering on failure. I would never have know this however, if it weren't for the ScanGauge.
So thanks ScanGauge!
Since the factory in-dash temp gauge doesn't even move until the coolant is at least in the 230* range (maybe higher), it's literally impossible to even notice that your system could be failing until you have a more serious problem.
Once I acquired my ScanGauge, I took note of the coolant temp at various times, conditions and loads.
I noticed that my truck ran around at 191-193* when the A/C was off. It really didn't matter the outside air temp, or if I was in stop & go traffic.
Crank up the air conditioner and the coolant temp is fine at freeway speeds. However, once you slow down to city traffic pace or just sit idling somewhere — the temps start to rise.
I experimented a little and sat in the sun on a 100 degree day with the A/C on max for exactly 15 minutes. I wanted to see how hot the coolant would get.
I started at 4pm & 193*.
Fifteen minutes later I was at 218 and climbing.
I'd seen enough — so I drove off to cool the truck down.
While driving around cooling off the truck, I got to thinking about the cooling system as a whole.
I had no idea when the radiator, coolant, thermostat, hoses, fan clutch and water pump were changed...if ever. The PO didn't keep records.
What I did know was that the temps I was seeing made feel like I was getting a good look into the
future of the cooling system. So I took the readings as an early warning sign of impending failure.
Now I just had to figure out what the problem was.
One thing that everyone talks about on here is the jiggle valve, but I quickly ruled that out as I could see the truck naturally wanted to be in the upper 180s to lower 190s. Only when the system was under stress, did the temps rise. So I knew the valve was oriented properly.
The fan clutch was my next thought, and I tested it while it was engaged and was unable to stop it with a rolled up newspaper. However, I'd never really heard the fan engage or disengage. So maybe bad maybe good.
The radiator was a suspect too ... well just because we always think it's the radiator.
Since I didn't know the radiators history, it was doubly suspect to me. Visually it looked ok. The fluid also looked ok (not great) but I knew it needed changing.
The water pump is scheduled to be changed next month with the timing belt, so I focused elsewhere even though I knew it could be the culprit as well.
After some thought, I've decided to just replace everything and not play games. I often have my little kids in the truck, so I really don't want to overheat because I'm being a cheap-ass.
So starting with the coolant which didn't look that bad to me when I popped the cap, turned out looking pretty nasty once I drained it.
I dumped in a bottle of Prestone flush and refilled with distilled water. I let that run for about a day or so and then drained it this morning.
After draining out the flush chemicals, I refilled it again. I left the cap off to burp the system and noticed white foamy stuff oozing very slowly out of the radiator. In the foam was little specks of crap.
So I decided to flush again but without the chems. Just wanted to get the last crap out before installing the new radiator with new coolant.
After refilling with straight distilled water, I noticed that the temps were a little better. Not by much, but enough to see that the Prestone flush did actually work as advertised.
So anyway, since I didn't feel like waiting for the coolant to cool off enough to swap radiators, I decided to just swap the fan clutch today and radiator tomorrow.
As some of you may have saw, I screwed myself on the clutch removal by not using any penetrating oil beforehand and not using a 6 point wrench.
http://www.toyota-4runner.org/3rd-gen-t4rs/220714-need-ideas-i-rounded-off-one-fan-clutch-nuts.html
3 nuts brook loose easy, the 4th (bottom nut I could not really see) nut felt like it was breaking loose — but turned out I was just making a nice shiny circle out of it.
Finally got the nut off and put the new clutch on.
The old clutch was the original and made it 20 years an 400,016 miles.
You can be damn sure I replaced it with another Aisin clutch!
So before the clutch replacement, I tested the coolant temp on a 100* day and saw 24* increase to 218* in 15 minutes.
After I installed the new clutch, I took it out for a drive and got it all warmed up. I then checked the coolant temp and made sure all the previous conditions were the same.
99* outside air temp ( not 100 I know — but hey ), A/C on full blast and truck sitting in the open sun.
Starting temp was 188*
After 5 minutes I had seen enough.
Ending temp actually went down to 186* after sitting in 99* heat with A/C cranked up to max. A/C exit temp was a frosty 40* the whole time too...
Tomorrow it's day 2 of the cooling system overhaul; the radiator, thermostat and hoses.
arty:
