Preventing HG Failure..

Hey guys, tomorrow I am going to pick up a 92 and the owner insures me it runs and drives good. Digging up history reports, it shows that it was serviced at dealers up to 133k but has 198k now. It did go in for its 70k service...so I "assume" that it has possible had at least one coolant change in its life and I am "praying" That when I go get it, there is no oil n coolant or over heating...The owner really can't tell me what he has done to it during his ownership of seven years besides let it sit for two and new battery...though he has said he's taken it to walmart for oil changes..eeek!

I hope that there is non and after a test drive all is cool because I really want to get this van but I would like to drive it for sometime before I have to think about engine replacement or headgasket...

What I am wondering about, since I can't find anything posted about it. How can I prevent HG issues?

I've read that the reservoir has a few tubes that can clog but I've not read anything about flushing. Should I flush the system with vinegar or something else? I've heard flushing a system can cause more harm then good sometimes. Should I just put a new radiator in? Just replace coolant?

Replace the coolant and the thermostat right away. Previa thermostats can fail closed (happened to my very neglected one). Toyota thermostats are actually cheap and replacing it is one of the simpler things on this vehicle. Keep a close watch on temp, leaks, etc for the first few hundred miles you have it, and unless you have reason to suspect something I'd leave everything else be.
Did you get the van?

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Originally Posted by Jonny

Replace the coolant and the thermostat right away. Previa thermostats can fail closed (happened to my very neglected one). Toyota thermostats are actually cheap and replacing it is one of the simpler things on this vehicle. Keep a close watch on temp, leaks, etc for the first few hundred miles you have it, and unless you have reason to suspect something I'd leave everything else be.
Did you get the van?

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Yeah I did get the van. I will do a post about it here in a sec. I bought a Aisin 180F thermostat...well ordered...I did a huge order to do a major tune up...I bought a few Toyato items but needing so much at one time, I was trying to save a few bucks if I could..

Get all the old coolant out by draining the radiator
And the engine by unscrewing the 10 mm bolt that's by the oil filter and is vertically oriented. Replace the thermostat at same time since will get more coolant out when pulling the hose off the water pump outlet where the stat is, use a Toyota oem stat.
Pull the reservoir and clean all three small tube inlets as they will all be plugged. I usually refill with distilled water several times to get all old antifreeze out. Then refill with toyota red plus distilled water to 50/50. I use pb blaster on the 2 thermostat nuts the day before as they will be rusted. Make sure rad cap is good or just replace it.