Full coolant flush tips?

[Jams]

Thanks a bunch Tim. With this information i think im gonna bite the bullet and pull the engine out. Ill probably only tear the top end down though. I think its leaking oil externally out of the HG. I could probably blast the block out with a pressure washer without taking the crank shaft and pistons out. This isnt what i intended to do when i bought the van but its gonna be a great learning experience. hopefully it pays off and i have an awesome van in the end haha. Thanks again!! James

[89van]

Apologies in advance for necromancying this thread, but I've recently got a concern about my cooling system, and about time too. Today I was just adding oil per usual, added too much so I'll have to sort that out :/ ,and out of boredom I took off my cooling junction cap and saw THIS!

I have very, very slim knowledge about cooling systems in general but given the almost rotting fish smell, and obvious soft buildup in the cap and the area in here

Something is definetly up!
Given the mostly previous unknown history this would be an ideal thing to do since I am keeping this thing. What would be the best course of action now? Drain &refill, flush, some sort of Prestone flush/clean additives or some thing other to do with the system? Any info is appreciated.

Thanks again in advance TVTPeople!

[timsrv]

Over time coolant gets acidic and will start eating the aluminum parts that are exposed to the coolant. A translucent white "gel" and/or white powder is a by-product of that corrosion process (and that's what those chunks look like to me). If you get a high quality coolant (like Prestone premixed 50/50) you can go up to 5 years and 50k miles. I always hit 50k miles in about 3½ years, so I change my coolant every 3 years.

If yours is older than 5 years/50k miles or if you don't know, replace it. You can also get "test strips" at most auto parts stores that will show acidity levels in coolant, but based on that picture I'd say it's way over due. I recommend draining from both the radiator and the block drains, then flushing and refilling with the Prestone 50/50 pre-mixed. If you opt for the concentrate, be sure to mix it with distilled water. Tim

[89van]

Is flushing out the coolant easy enough to do in my driveway? I know someone said there was a drain on the bottom right? corner of the radiator, but from the block I'm not so sure where they are located unless it was posted here earlier in which i'll comb back through to see.

Thanks again tim.

[timsrv]

I posted a picture of the block drain location in this thread (post #10). It can be done in the driveway, but don't let the coolant go on the ground (It can be hazardous to pets and other wildlife). I'm not sure about where you live, but here the local Napa has collection bins for free disposal of engine oil & antifreeze.

Just draining and refilling the engine/radiator is probably good enough, but if mine looked like yours I'd probable flush it thoroughly for at least 15 minutes. Tim

[89van]

Hey tim, finally getting around to doing this flush today. Found the radiator drain plug and let it empty itself. I believe I found the block drainplug in that not-so-easy to access area behind the alternator and under the manifold, going to see if I can crack that one at all. Gonna put some nice red coolant in it afterwards and see how she does!

Also, havent found much info about the coolant reservoir removal, is there any way to remove it? On top it seems to be pressed into the body under the drivers seat unless theres some magic hidden bolts behind the bracket. Have some old coolant in it and I am also looking to remove it and clean it properly. Thanks again

[timsrv]

The recovery bottle can seem impossible to remove, but it will come off with hand pressure. Basically you grab it firmly with both hands and apply a constant upwards pressure while rocking it from front to back. The plastic bottle has a groove in the back and the metal bracket slides vertically in that groove. It gets tight when it's fully seated, so the initial upwards force to remove can be a bit of a struggle, but the rocking motion helps to get it free. Tim

[Gareth]

Also, be aware that if you remove and clean the coolant overflow bottle, you're very likely to damage the grommet for the low coolant level sensor (if you have one). Which will cause a leak. I certainly did (well, might have already had a leak there beforehand, but the grommet basically disintegrated on me when I had the bottle out).

Luckily, through the forum, I found out that Dorman PCV Valve Grommet 42055 is a perfect replacement!

[samstrader]

I have a Previa. Has anyone installed a filter on the coolant to keep it clean? Like the coolant filters diesel engines sometimes have.