I'm about to tackle a radiator replacement on my 2000 and I've got some questions.

1. Since I am literally removing and replacing the radiator, do I still need to flush the cooling system? It's running Toyota Pink since before I got it, the coolant appears to be nice and clear of contaminants as best I can tell. I will be refilling with Toyota Pink as well as using a genuine Toyota radiator and hoses I picked up from the dealership, if that makes any difference.

2. I also want to replace the thermostat while I have the system drained as I am uncertain as to how long it has been since it was last replaced.



What all of this do I actually need to remove to get access to the thermostat?

3. My firewall-mounted heater control valve has apparently seized so I'll be replacing that at the same time. Any tips on this? I have the automatic climate control, but I do not have the optional under-seat heater core - just the standard in-dash one.

Thanks in advance!

1) I wouldn't but you can if you wish. Your basically flushing it by changing the antifreeze.

2) you just need to remove the 3 bolts in the housing to change the thermostat. Just put the jiggler at 6 oclock.

3) Those do get brittle. So be ginger around it.

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How do you get access to the three bolts in the housing? It looks like the timing belt cover blocks access on mine.



Or are there access holes for tools in the cover that I'm not seeing? Thanks.

Replace the radiator cap with an OEM one as well. It will be time.

There are three nuts that hold the thermostat housing to the block on studs. Not too hard to get to once the lower hose is removed. Tighten to 14ft pounds. Don’t forget a new thermostat gasket.

Just make sure when changing the valve that its setting is on COLD on the AC controller before changing it out. Also check to see that the cable moves freely.

I indeed bought an OEM cap and thermostat gasket based on some of the prior threads I read here and they are on my list of things to replace.

Just confirming - there's no need to pull the timing cover to get the housing out?

I did a radiator replacement on my friend's 03 Tacoma few days back. I opened the drain valve under the radiator and collected all and used it (not the very bottom residue).

Thermostat is located at the bottom inlet (near the alternator) and not at the top outlet. If possible install OEM radiator hoses and reuse OEM clamps (never apply any lubricant when installing the hoses.

Also clean the reservoir cap and make sure nothing is clogged in the cap.

no, you don't need to pull the timing cover. looking at the front of the engine, it's on the lower right.

Best access to the T-stat housing is form the Bottom side, not the top. Now, while this was a full belt and water-pump job, I'm more just trying to show the location of the T-stat housing:



It's at 5 o'clock, the darker metal pointed down and right in the frame (and has the lower radiator hose on it in this photo). 3 nuts, evenly spaced.

As for the rest, I always take the opportunity to run some coolant system cleaner/flush for a few days before doing a swap, then do one quick flush with distilled water (10 minute drive, just get to temp to open the T-stat). Overkill? Maybe. For the "cost" of about $10 and 10 extra minutes of time it just seems like a no-brainer to me. I go Much more in-depth when I first buy a used vehicle (multiple cleaning flushes, multiple "rinse" flushes over weeks of time) because you have no clue what some PO did, or didn't do. My 4-runner had green coolant, and gooey globs that flushed out.

Here's a video from mtbtim. It covers a transmission cooler install (not what you asked for), but it also covers radiator and thermostat replacement.

YouTube

No need to pull timing belt cover. Follow the lower radiator hose up to the engine. That is where the thermostat is. 3 nuts and the torque amount is in the thread here.

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Flushing before swapping is unfortunately not a possibility with my truck at the current time. I had already been preparing to preemptively replace the radiator this month but both tanks lost containment in the parking lot last week; the vehicle won't hold pressure and will piss out most of the contents in minutes.

I forgot I also replaced both coolant lines going to and from the control valve. It looked like one had been leaking for some time. In 2013 they weren’t too expensive. If you plan to keep the 4Runner for some time it may be a wise investment.

Yes might as well replace those hoses if you are replacing your control valve. Lots of heat coming off the engine around the control valve. I cant say I had one stick on me. I have heard of them busting on users. Though.

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Before you take everything apart drain radiator add distelled water and radiator flush . Do that twice then you know its as clean as you can get it, then add new parts , just a suggestion.also flush engine with both hoses off engine

If you let the coolant dribble out of the petcock at the radiator bottom for about 20-40 extra minutes before undoing the thermostat housing, there'll be less coolant blurping out when you pull the thermostat housing. Once you pull the thermostat housing and the coolant that's in the engine all drains out, there will only be about a quart still left in the engine. Use distilled water if diluting. Just refill with the pink, or the diluted red, and you'll be huge.