brandon

Today while driving, my 4runner overheated. The needle was all the way to the right, but went straight there instead of gradually getting hot.. I figured that all the water had leaked out of the radiator.... My question is this. Since it was runnning so hot, what all could have been damaged. I had to have it towed home since it would not crank right away and I did not feel like leaving in the bad part of town. It cranked when it got home, but I am going to check/replace the radiator since it has needed to be fixed for quite some time, as well as the thermostat. What else would I need to check?

Travis

Few things are worse than an overheated engine. What engine model and year was the motor?

I had a similiar experience because of a numbskull dealer mechanic. After doing some routine maintenance (timing belt, fluid flushing, belts, etc), the mechanic forgot to refill the coolant system. Apparently he flushed the system and then never completely refilled the radiator. I got 5 miles down the road when the needle jumped. I opened the radiator to find it empty.

We fought over the bill and they agreed to pay for half of the repair work that now needed to be done. So depending upon your situation, you will probably need a lot of work (head gasket, valve job, rings possibly, water pump, etc).

Anytime the motor gets pulled apart, it becomes a good time to do all kinds of work - new timing belt, water pump, hose replacements, valve cleaning, fuel filter, etc).

Most of the time when a Toyota motor gets hot, you're looking at $1000 in work.

T

brandon

its a v6 3.0L

sherri_girl

Heat really kills the electrical. When my Runner had an overheating problem, the engine started "cutting out" when I was driving it. I thought it was fuel, but it turned out to be the pick-ups in the distributor. I'd also change the engine temp sensor. Also make sure that the bottom radiator shroud in there, it really help in the cooling, especially if your runner has A/C. It's a thin, long plastic strip that clips to the bottom of the full shroud.

Worse case scenario, the head could have warped.

growinseed

I'd replace/repair radiator leak,check/replace water pump, replace t-stat, and coolant with reverse osomosis water (the kind from the vending machine) engine oil and see if it will run. don't dirve it. Next check for vacuum leaks, compression, coolent leaks internal (pressure test and oil chem test). If this checks out you may have been one lucky guy. Flush cooling system a few times with RO water and go back to your blend.
The major problem with overheating an engine is it can cause the different metals to warp and or crack as they heat and expand/cool and contract and differnet rates.
If this stuff doesn't check out travis called it. One thing to consider is 'when your there replace it'. if you have to replace head gasket take the head to a machine shop and have them check it out
A final Thought: Find the source of the overheating it makes no sense to repair the engine if you don't know what caused the problem in the first place.

sherri_girl

Good point. Did you recently have the 3VZ headgasket recall done? I have heard of techs putting the head gasket on backwards. Or have you been driving it awhile and it just did this one day?

brandon

It just started to screw up today. I sure hope I didn't mess anything up woth $$$$, such as the engine or any of the metal parts like you guys/girls were referring to. I have ordered a new radiator, as well as the t-stat. After those two things are replaced I guess I will see what happens. The shop that I take my 4runner to is a Toyota Dealership owned by one of my father's good friends. He is about the only person I would trust to tell me the truth about what else needs to be done. The only problem is, that the dealership is 2 and a half hors away.. I really don't want to drive the 4runner up there if I still don't know if everything is ok. I was thinking of towing it on a trailer or something. Any ideas?

Jay

If you could not crank the vehicle, sounds like it was really hot. The reason you could not crank it was because the pistons swelled up tightly inside the cylinder bore. I suspect the cylinder walls and piston skirts to have been scored.

The only way to tell, is with using a bore scope to look into the cylinder and visually inspect the cylinder walls for scoring.

I realize the shop is a long distance away. Be it, the damage is probably already done, I still recommend towing the vehicle.


(I have not seen any mention of the vehicle running rough, so I dont suspect it to be as simple as a blow head gasket.)

Man, I hope Im wrong.

Jay

brandon

I had to have the 4runner towed home, but when I got it home, it cranked up and I was able to drive it off the tow truck and into my driveway. Good sign?

Jay

I still wouldnt run it until I bore scoped it.

Jay

brandon

ok well I finally got the radiator and thermostat changed, but the engine is still over heating. I talked to a friend here, and they said that toyota's are bad for new thrmostats not opening up and gave me a few suggestions on how to fix that. Any other ideas on what could be the prob?

sherri_girl

Please check your bottom radiator shroud. I changed the works on my runner, only to find out it was that. It is a long, thin plastic strip that is clipped to the bottom of the full shroud. It doesn't look like much, but it made all the difference. Also it might be the water pump? I dunno, I just changed everything till I found the problem (fan clutch, therm, rad, temp sensor, water pump...)

Jay

New Toyota Thermostat? Or aftermarket?

I would doubt the thermostat to be stuck if it was a toyota part. But wierder things have happened.

Are you POSITIVE you got all the air out of the system when you refilled the coolant?

The technique I use on a complete refill works great for me. I remove the upper rad hose from the rad top tank. I bend the hose up at an angle suitable to be able to pour from the jug. It can take a full gallon here alone ( filling the engines coolant passages ). At the point the coolant is rising up the upper rad hose, I quickly reattach the hose to the radiator and secure the clamp so I dont forget. Next I fill up the radiator just above the tubes inside it, so I can leave room for the coolant to expand, and at a low enough level I can see when the thermostat opens by watching for the coolant to start flowing. Now I run the engine, and monitor the level. After I see the thermostat has opened and coolant is flowing, I then top off the radiator and install the cap. Fill the coolant overflow tank. Test drive the vehicle. Lastly, if all possible douple check the coolant level the next morning, and replenish the resivoir as necessary.

If after you are sure the cooling system is bleed properly, the vehicle is still overheating, you are going to need to have the headgaskets inspected. This will require one of several methods. My favorite is with a leak down tester. This tool has a hose that screws in to replace the spark plug. With the engine on top dead center ( valves closed ), and pressure applied to the cylinder, you watch the level of the coolant. If the head gasket is blown, you will see a rise in the coolant level. ( you can fill the radiator to the point is just about to overflow, then plug in the hose ) Each cylinder needs to be inspected. Another common test, which I dont like very much, is whats called the Block Tester. This uses a fluid that reacts to Carbon Monoxide and changes color. The device is used at the mouth of the radiator. This test is easy to screw up, and get incorrect results.

I still fear for the fact you have been running the engine without confirming the cylinder walls are ok. But, I suppose the damage would already be done. My biggest concern is to what caused the engine to lock up, and im sure there is evidence somewhere. You need to have the engine bore-scoped and pressure tested.

Jay

p.s damn, sorry so long

brandon

I am still taking it to have it inspected. I just wanted to get these things done myself. I am still towing it up to the dealership to be fully inspected. Thanks everyone for all your advice.

toddowaddo

Jay, thanks for the refill tip. That sounds easier than the mess I made last time I flushed my radiator.