Ilovemountains

Im 99% sure the 1993 pickup I bought is going to need a complete rebuild… The guy I bought it from claimed the timing chain was done, and it does have RVT sealant around the cover and the cover looks pretty clean, with a genuine Toyota water pump.

I bought it about a month ago and have been tinkering with it in my spare time, I’ve replaced the cap, rotor, wires, plugs, filters, manifold back complete exhaust, flushed the coolant and installed a new temp sensor and a dual stage thermostat, oil and filter, trans gear oil, rear diff,put a clutch kit in it and a complete manual to power steering conversion.

Fast forward to this past Monday, I took it on about a 150 mile round trip ride to pick up some motorcycle parts. When I stopped at the midway point I smelled coolant, I popped the hood and took a look around, everything looked OK but the overflow was down about an inch. I pulled the oil cap and it’s a little milky but not terribly bad, the dipstick looked good as the oil only has a few miles on it. Anyway on the way home I started to notice a slight knocking sound, right when I would let off the throttle and push the clutch in to shift. I was about 10 miles from home to I just took it easy and pulled it in the garage, now the coolant reservoir is full again….. not good so I grabbed an old towel and popped the rad cap, it depressurized and the coolant level in the radiator was bouncing up and down with the engine off.

Anyway I have a bad feeling that the head gasket is bad, and the knock is probably a bearing from coolant mixing with the oil. I’m going to warm it up and do a compression check on it tomorrow and check the timing, Im pretty upset, its still making excellent power, no steam from the tail pipe and the oil appears to be clean and golden. This thing just turned into a complete money pit on me! Any thoughts, words of wisdom or ideas would be greatly appreciated!

JJ'89

You sound like me...something seems wrong; immediately start worrying about worst case. I'm not a pro, but I'd drain the oil, and examine (magnetic drain plug would be nice), cut open carefully the filter and examine. If you have time, get a good warm "clean catch" oil sample and send it in for analysis. Leakdown check (borrow/rent from one of the parts places that do that) on the warm engine. Stethoscope (improvised if you don't have access to a real one) and check for noises try to localize and pinpoint if necessary. Check warm engine oil pressure if you have a real indicator. I'd say no steam from the exhaust is a good sign, but doesn't totally rule out a gasket failure. When you're thinking bearing failure, little noises suddenly get your attention. Good luck and keep the audience updated. My $0.02

Co_94_PU

iTrader: (-1)

If you suspect damage the worst thing you can do is run it, drop the oil pan and inspect it! The cost is less than 30$ (oil and new gasket goop) before you risk destroying a much more expensive part like the crank by heat cycling it with questionable oil. If you catch it soon enough you might just need to replace a bearing, wait and you won't even be able to get a core charge refund for the crankshaft and are going to need new rods maybe a new block ect..

Pulling the valve cover to inspect the upper end costs nothing but time..

Ilovemountains

I agree, I rented a compression gauge and a block test kit yesterday, Im going to run it one more time to get it hot and check them today, while its warming up ill shoot it with the timing light. Its just frustrating that it was running great the day I bought it, Ive not ran it hard at all and have fed it quite a bit of new parts and less than 300 miles here it sits at just a shot over $3100 invested, not sure if the guy I bought it from knew it was a time bomb or not but it sure seems that way, guess thats the gamble you take when you buy anything used, especially a 24 year old pickup!

JJ'89

How many miles? I don't know the exact issue with antifreeze contamination of the oil. I have read that most antifreeze contains silicon is some form, and we know that silicon is a component of some abrasives. You state that the oil does not appear to be contaminated. Even if it would be contaminated imperceptibly, I can't imagine that causing bearing failure in those few miles. If you don't need it for daily drive, an oil analysis would be useful. Leakdown check more useful than a compression test. Have you done some searches on search engine and utube for something like "troubleshooting a suspected headgasket failure" etc...

Ilovemountains

Today I checked the compression, I got 170 or so across all 4, I also used the block test kit and with 2 tests the fluid stayed blue, I also jumped the diag pins and checked the timing, spot on to 5. I do notice some strange things with the cooling system, it seems to purge quite alot of coolant if ran with the cap off rather than circulate it, Id say I had to drain it down a half gallon just to keep it to the top of the radiator core to do the test.

The truck has 159,000 miles on it, Im the 3rd owner, the guy I bought it from never had it titled in his name but nonetheless he owned it for a brief time. Im going to make an apt at the local import repair shop and have them take a listen, lead down and check the valves and all as I just dont have the time right now!

JJ'89

"Purged" ? If you mean that coolant comes out of the open-to-the-atmosphere filler neck when the engine comes up to operating temperature...that would be normal. Coolant expands with increasing temperature. Modern (last 50 years or so) cooling systems have a closed coolant system. coolant exits the radiator when the expansion in a full system causes a pressure sufficient to unseat a relief valve in the radiator cap. The coolant flows through a tube to a reservoir. Assuming a tight system that does not admit air, the coolant contracts during cool-down and flows back to the radiator. In a system that is normal good comdition, there will be very little if any air in the system. That's good cuz air is oxygen facilitates corrosion. Old cars like my '65 Chevy have open system. The cold engine level normal is about an inch and a half below the rim of the filler neck. Space allows expansion. People who don't know, fill it to the brim cold, and it "pukes" (vents) overboard as it warms up. Self-adjusting, but tough on the environment and local doggies and kitties if they have a sweet tooth...