1991 22RE 204000 miles
OK, found my intake manifold gasket leakin while troubleshooting other problems. Today, replaced all intake gaskets and thermostat. Got it all put back together and filled with water. Checked oil and low and behold, its milky. Can the intake manifold gasket cause milky oil ? Or does that lead directly to blown head gasket ? And if head gasket, is it worth rebuilding an engine with 204000 or just get a new crate engine. This is my hunting truck I use to save miles and wear on my new truck. All advice is very much appreciated. Thanks

 

I'd do a quick compression check (with the squirt of oil to check the rings, because you might be losing compression through the head gasket). Maybe even a leakdown test, if you have the tool (but since that's really a comparison test, it won't help much without a prior reading).

I replaced the head gasket on mine at 157k miles, and I'm glad I did. But mine was a Calif truck, so the rest of the truck was rust (and mud) free. So I don't think its the total miles, but where those miles were. How's the rest of the truck? Good enough to put in a crate engine? Then I would lean toward rebuilding. (But, of course, I'd look carefully at the cylinder walls, I'd check all the usual bearing clearances, I'd have the head pressure tested, and I wouldn't get so invested in the process that I couldn't give up if it turned out I should).

 

The rest of the truck is in ok shape. I use it in the woods so it has some dents and dings. The transmission shifts good, drives good, 4wd pulls good. No other mechanical problems I can see. Had good power and no smoke or anything. Thanks.

 

When did you notice the milky oil? Do you check your oil regularly, so this might be a new issue, or it might be old. @204k miles I'd say you are probably do for a timing chain, unless you have info to support otherwise. The chains are good for around 100k miles or so. The real problem is the stock Toyota plastic guides that break causing the chain to wear through the timing cover, which develops into an oil/water martini.

If you pull the valve cover and look down along the chain, you should be able to see if the big plastic guid is still along the driver's side or if it is broken and missing there could be two grooves in the timing cover where the chain has been grinding.

If you're mechanically inclined, a timing chain, cover, and head gasket is a weekend job. The suckiest part is dropping the oilpan to clean out the busted chain guide pieces. There are a lot of walk-throughs with tons of pictures on the forum here to help you out.

 

Or it could be condensation or water sucked up through the vacuum return to the crankcase or breather.

Change your oil and run it for 10 minutes to see if the water comes back.

 

I check the oil every morning before starting. This has really put a damper on my hunting season. I have a shop and tools. And I am mechanically inclined. Just never been into the head of an engine. Mostly done simple stuff like carburators, lots of work on atv's.

 

You said that you replaced the intake manifold gasket already. You've torn into 50% of the job already. Really.

Once you split the intake from the head, split the exhaust manifold from the head, then boom the head comes off. If you need to replace the timing cover then you have to split the power steering pump and alternator. The alternator comes out, but the PS pump can just be flopped over to the side.

First do some diagnostics though. Check the timing chain guides and do a compression test. Although, either way the end result is pulling the head. You can be back on the road on the cheap side for about $200 or more depending on what you do while you're in there.

Personally I would take this time to replace the cam with something that is a little more punchy. I you are running 4wd a lot or have bigger tires, you can get a cam from engnbldr that puts out more torque down low when you are crawling along. They're like $90 and make a big difference. Probably the best money I've spent on the truck so far.

 

Thanks for all the advice. I'm going to tchange the oil in the morning and see if it milks again. If it does, I'll pull it in the shop and just take my time over the winter months going through it all. I figure if I'm in there, I may as well change or make better everything in there. Thanks again.