87 Sr5 Overheated Now won't start

[grimes403]

Hi, Ive been browsing these forums for a couple years now this is my first post. I am trying to diagnose a problem that I can't seem too figure out. I have an 87 sr5 the least rust on a terc i have ever seen. I was driving it today and all of a sudden could smell burning so I look at the temperature gauge and its in the red. I turn my tunes down and I can hear what i think my valves rattling so I pull over and as I am doing so the car stalls. The rad fan was not working so i think thats why it overheated also there was antifreeze leaking out of the exhaust but it might have been the overflow spraying as there was no white smoke coming out the back. Also there is no coolant in the oil so i dont think its the head gasket. I let it cool down and try to start it again no dice cranks but won't fire. So i get it towed back to my house and start to go through things first I take the cover off the timing belt to check and make sure the timing belt is there because when i crank the motor it sounds exactly like when i have wrecked the timing belt on other vehicles. The belt looks fine i got someone to crank it while i watch with the cover off it belt spins gears spin. Next i take the plug wires off I have spark. I know it has nothing to do with the fuel pump but i can hear it going. So i have fuel and spark what am i missing compression?

[Petros]

Welcome to the list!

Sorry to hear about your problems. It is almost certainly the head gasket, not enough compression to run it, it will run on 3 cylinders, but not on 2, so likely two adjoining ones, likely one and two (they run the hotest). You can do a compression test, but coolant coming out the exhaust is a sure sign. Pull the spark plugs and have someone crank it, stand back or you will get sprayed with coolant, just to confirm. Much faster than a compression check. Also, when it cranks, if it is an uneven cranking: chug, chug, whip! chug, chug, whip! also sign compression bad in one or more cylinders.

Follow my procedure as outline here:

https://tercel4wd.com/forums/viewtopic.php?f=7&t=6059

You can fix it for just the cost of the head gasket and the header pipe gasket, perhaps the by-pass tube o-rings if yours are bad. I list the tools and supplies you will need. looks like you will have something to do this saturday.

Good luck.

[grimes403]

Thanks for the quick reply! I took the spark plugs out and cranked it sure enough coolant...also the uneven cranking you described...makes a lot of sense my father has been telling me that car had a bad cylinder for a while...this will give me a good opportunity to check intake and exhaust valves which i've been procrastinating about checking for a while...that procedure you described doesn't look too difficult one of the reasons i love these cars i am going to go through it next weekend i have off and update

[Petros]

If you are going to have the valve reground, I highly recommend replacing all 4 exhaust valves, the intakes can be reground, and of course new valve stem seals. The machine shop will want to crack check the engine, I would not bother unless it is very badly warped, it is a waste of money they never crack.

[grimes403]

so i finally took the head off and the gasket appears to be fine the valves also appear to be fine...i am going to put it back together with a new gasket regardless is it possible that maybe the old gasket is screwed and its just not visible what else could be the problem?

[dlb]

i would look very closely at the head gasket. the damage necessary to cause the symptoms you describe doesn't usually look catastrophic at all. you might also check for cracks between the cylinders--not likely but possible.

maybe take some close up pics and post them here.

[Petros]

if the engine was overheated, uneven cooling in the head will cause the gasket to lift between cyl. one and two breaking the seal. So it will leak sealant and have little/no compression, but the gasket can look fine.

If you are worried about defects/cracks in the head a machine shop can check for cracks, but cracked heads (or blocks) are pretty rare. Even if you can not see it, it is almost certain the head gasket was bad, you did have coolant in the cylinders, no way for that to happen without a bad headgasket (or a severe crack in the head or block, very unlikely).

Resuface the head and top of the block so it is flat as I show in my procedure (check the head for being flat very carefully, if in doubt take it to a machine shop after you clean off the gasket material and they will check it for being flat).

Install new valve stem seals and new exhaust valves, and than a new head gasket per my procedure, it will run for another 100k miles if you keep it from overheating.

[grimes403]

That makes perfect sense I think I was just expecting the head gasket to look way worse as this is the second time I have overheated the car and I saw your picture of the gasket melted between cylinders. Makes sense that the heat would cause the gasket to lift. Honestly the motor looks pretty amazing for a 25 year old car I'm going to clean it up and make sure its flat but just eyeballing it after I took it off I can't see any problem. Like you say once I get it cleaned up if I am unsure I will take it to a machine shop. Thanks for the help I will post some pictures later when I get back to working on it. This is the first head gasket I have ever replaced myself and so far using your procedure its been a piece of cake! Makes me happy that I have 3 of these cars, great cars for someone who wants to learn how to "diy".

[dlb]

make sure your torque wrench is accurate for torquing up the head bolts. incorrectly torqued head bolts will cause premature head gasket failure so be exact. one member on this forum went through a few head gaskets before he checked his torque wrench and found it was faulty.