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Discussion Starter · #1 ·
So my head gasket is shot. It has ran hot like 3 times in the last month. It ran hot a week ago. I let it cool down to regular running temp and then drove it about a half mile or so to my work, and left it there. Well when I return from working out of town fo a week (not in the yota, in a work truck) I bought a thermostat and a belt to replace the radmomly squeely belt that runs the water pump.

I go to check my water and notice white spots on the radiator cap, and no water in the radiator. Uh oh. I take the oil cap off and yep, there it is. :headbang: Theres where my water went. Ive only put 1200 miles on the truck since I bought it with 140,000 on the odo. I had all the fluids changed after about the first 150 miles I put on it. I have a few questions.

I have another vehicle I can drive for now, but do NOT have the $ to fix this right now. I do not want to do this myself... ...or do I? If it will be a week or two before I can get to it , Do I need to drain all the oil/Water? One of my buds say yes, so it wont rust. Another one says no, theres enough oil in the water to prevent rust, and If i drain it, it might just leave water, then it will rust.

Ive never had this happen, and could really use some assistance
 

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Soylent Green sales
rock crawler
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I say drain it. I'm not worried so much for rust, but the crank bearings and such don't like the water at all.

Drain and refill, run for a minute or so to circulate, shut off and don't start again. my $.02
 

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x2 on the drain and refill. Water mixed with oil can kill the bearings quick. You may want to add some Seafoam to the fresh oil since it has isopropyl alcohol in it and that will absorb the water. Run the motor briefly to circulate as fourwd1 suggested, then drain it again to get rid of the water. If there's a chance the motor will be run again, refill with oil.
 

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Toyota Owner
1994 Toyota Pickup
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Timing Cover

It's possible that the timing chain ate through the coolant port on the inside of the timing chain cover causing the leak. I think it would be worth taking off the timing chain cover before the head to see. It could save you some work. But with 140,000 miles maybe you would want to change the head gasket while you are in there anyway.
 

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Discussion Starter · #6 ·
The timing chain, Is this pretty common with toyotas, seems like ive heard that some where before
 

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Discussion Starter · #7 ·
It's possible that the timing chain ate through the coolant port on the inside of the timing chain cover causing the leak. I think it would be worth taking off the timing chain cover before the head to see. It could save you some work. But with 140,000 miles maybe you would want to change the head gasket while you are in there anyway.
When I took it to the shop, I asked them to replace the chain while they replaced the head gasket. I called them today to see how things were going. The timing chain DID eat thru the plastic guides. It started to eat into the coolant port, but luckily didnt get far. Thanks for heads up.

The culprit... Mud in the radiator fins causing it to overheat and blow the gasket.
 

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The culprit... Mud in the radiator fins causing it to overheat and blow the gasket.
Thanks for the update. This is a good reminder for all of us.
 

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Procrastinating on TN
'93 Pickup
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Yep gotta hose that sh*t off when you get home :smokin:
 

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Discussion Starter · #12 ·
I think the truck was sold to me with the gasket already heading out the door.

You're right, it is a bummer about the expenses. But to be honest, Its not too bad.

I know now that it had been recently looked over by a qualified mechanic. The top end has been went thru and inspected. My heads have been machined and are good for probably the rest of the life of the truck. I probably won't ever need another head gasket. The piece of mind that the timing chain won't come and bite me in the ass out of the blue. And as a consolation prize, a fresh oil change, lol.

I really like my truck. I got a good deal on it, and Im getting it back knowing that it should give me many many more miles out of it.
 

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HiluxSupraISF
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I think the truck was sold to me with the gasket already heading out the door.

You're right, it is a bummer about the expenses. But to be honest, Its not too bad.

I know now that it had been recently looked over by a qualified mechanic. The top end has been went thru and inspected. My heads have been machined and are good for probably the rest of the life of the truck. I probably won't ever need another head gasket. The piece of mind that the timing chain won't come and bite me in the ass out of the blue. And as a consolation prize, a fresh oil change, lol.

I really like my truck. I got a good deal on it, and Im getting it back knowing that it should give me many many more miles out of it.
did you get the ports polished and removed any castings before you put it back on? lol

Sounds like a really smooth move right there. As long things went fine and the truck runs well again, i'd be happy too! lol
 

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Discussion Starter · #14 ·
No, and I take it if I didn't ask them to, they didn't. Damnit
 

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Discussion Starter · #15 ·
Called them today to see how much this is going to run me, I asked about port polishing and he said "everything was good". Can anyone go into a lil bit more detail about the ports and castings, Youll have to excuse me, I was never any good w/ engines.
 

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HiluxSupraISF
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basically the heads are casted, where they fill in the metal and just pull out the forms and stuff.... while the motors are just mass produced back in 1994, Toyota of course wouldn't take their time to go in and remove any rough edges and spots in the ports and chambers and stuff.

For example, ever had any plastic item and see those seams on some side of it where they injected plastic? its a very similar concept of removing the rough edges..


lol wikipedia it
 

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Discussion Starter · #17 ·
Ah... Gotcha. Nice example
 

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Procrastinating on TN
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Removing rough edges is probably good, but you won't notice a power increase. When I replaced my head I purchased and RV Head with Polished Ports and a High Performance cam. While my motor is running great due to completely new valves and everything, I did not have any noticeable power increase. Polishing is not that important, especially on these low power motors, and is actually a bit of a myth. In the end these are slow trucks and some minor head work is not going to change that even a bit. Sorry to be a party pooper ;)

Very interesting read taken from good ole' Wikipedia:

It is popularly held that enlarging the ports to the maximum possible size and applying a mirror finish is what porting is. However that is not so. Some ports may be enlarged to their maximum possible size (in keeping with the highest level of aerodynamic efficiency) but those engines are highly developed very high speed units where the actual size of the ports has become a restriction. Often the size of the port is reduced to increase power. A mirror finish of the port does not provide the increase that intuition would suggest. In fact, within intake systems, the surface is usually deliberately textured to a degree of uniform roughness to encourage fuel deposited on the port walls to evaporate quickly. A rough surface on selected areas of the port may also alter flow by energizing the boundary layer, which can alter the flow path noticeably, possibly increasing flow. This is similar to what the dimples on a golf ball do. Flow bench testing shows that the difference between a mirror finished intake port and a rough textured port is typically less than 1%. The difference between a smooth to the touch port and an optically mirrored surface is not measurable by ordinary means. Exhaust ports may be smooth finished because of the dry gas flow and in the interest of minimizing exhaust by-product build-up. A 300 - 400 Grit finish followed by a light buff is generally accepted to be representative of a near optimal finish for exhaust gas ports.

The reason that polished ports are not advantageous from a flow standpoint is that at the interface between the metal wall and the air, the air speed is ZERO (see boundary layer and laminar flow). This is due to the wetting action of the air and indeed all fluids. The first layer of molecules adheres to the wall and does not move significantly. The rest of the flow field must shear past which develops a velocity profile (or gradient) across the duct. In order for surface roughness to impact flow appreciably, the high spots must be high enough to protrude into the faster moving air toward the center. Only a very rough surface does this.
 

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HiluxSupraISF
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Hm... I guess you could be right then! let's get this boat sailing then!

how long til you get your truck back?
 

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Discussion Starter · #20 ·
This Friday when I get back into town I hope. What I dont understand is I put 400 down when I dropped the truck off. He quoted me about 6 to 700 for the head gaskets to be replaced. I asked him before he started on it to check the timing chain and guides, and to replace them. Now the price is from $6-700 up to $1200. Is this fair?
 
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