loke

I'm trying for some wishful thinking regarding my motor. Hoping just a head gasket but expecting the worst.

Here's the story, hopefully someone can give me some ideas before I tare into this thing. My 86 Pickup has over 200k miles. About 15k earlier it got a new head entirely. I was on a trip into the mountains from the Phoenix desert heat this passed weekend. Temps were close to 100 and I was traveling at 65 miles per hour or so on 6% grades slowing me down to 50ish. The truck really hates this and will bog down until I'm trying to keep up in traffic with third gear.

The truck seemed to make it ok and since I was heading into the wilderness I stopped to fill up my gas after about 80 miles. I should have checked the oil but it was ok before leaving and I never had a problem with burning oil before. At this point I'm up around 5000 ft, temps are down to 60's and the major mountain grades are done. I travel 6 easy miles and begin hearing a rattle sound while under power. Get off the gas and all normal sounds, even at 3000 RPM. Hit the gas and hear the rattle. It goes away after a few seconds so I continue like normal. The truck is a bit of a rattle trap so it wasn't entirely out of the ordinary. Within 30 seconds of the sound going away, I hear a pop and hiss, like a hose blew under high pressure. Immediately I see smoke or steam, its hard to tell. It wasn't dark colored.

I pulled over immediately and as I slowed down the engine stalls out. I popped the hood and my coolant is boiling in the overflow tank and there is a bit of coolant dripping from the engine. I couldn't tell exactly where it came from but no hoses seems blown and the dripping stopped quickly. I let it cool for about 30 minutes just hoping it over heated but I checked the oil and it was bone dry. I added a few fresh quarts.

After about half an hour I tried to fire it up. The motor made a sound like the starter whining and not catching. I had a buddy try while I observed and I could see the belts turning (fan, alternator, A/C, etc) so I assume the engine was turning over but there was no grunt to it like a cylinder firing. I could also hear a slight hiss form the head region. There is also no rattle, or suspicious noise, just a whine and hiss. Like it was turning a dead motor, no fuel or spark.

Now I really don't know what I'm doing regarding troubleshooting issues I've never seen. I'm good with a wrench and thankfully and can do most of what I'm directed to do but I've never seen this exact issue so I'm only speculating. Since it seems things are turning, I don't think its seized. I'm guessing blown head gasket is causing a complete loss of compression. This weekend I'm going to dump the oil and coolant and check it, as well as do a compression check. We'll see if there is any smoking gun. Any thoughts are welcomed and appreciated. Like I said, I haven't ever needed to troubleshoot an engine like this. I need fuel, spark, and compression, right? Any suggestions on how to check everything? Its my toy vehicle so as much as this sucks, I'm looking on the bright side and will try and enjoy the project.

loke

Here are some pics of the offending vehicle.

thook

Fuel, spark, compression...yep.

Kinda does sound like you blew the gasket. And, it sounds like you already know what to check. Can't really offer more than that until you've looked at it all. From the some of the description, though, hopefully the timing chain's not involved. But, what are the chances of blowing a head and chain at the same time? I don't know. You know if you pull the valve cover off and look at the timing assembly.

loke

Thanks for the response.

I checked the compression today. Each cylinder pulsed 10 psi or so, topping out each turn at 35 to 40 psi, holding at 25-35 psi. I was kind of expecting more of difference between each reading. Does this indicate anything odd? I don't have much experience with the compression tester.

What I'm thinking this has told me, is that since pressure built and pulsed, my pistons are all moving, meaning no seized rings or broken rods. The damage to the head gasket was only allowing ~30psi to hold. Am I on the right track? Any way to further tell if the rings are holding pressure?

vital22re

iTrader: (2)

try adding a teaspoon of oil to each cylinder and test compression again. Battery needs a good charge. unplug the coil and hold the throttle open when you crank. Crank the motor for aleast 5 seconds. What do your plugs look like?