desertrat666

Hello everyone,

I am a first time poster.

I have a 1998 Toyota Tacoma that is overheating.

I have replaced the radiator (oem) and the thermostat (stock) and the engine continues to overheat. After the engine overheats if I lift the hood, steam is blowing out the radiator overflow hose which leads me to believe the problem is due to coolant not circulating (which is why I replaced the thermostat).

I am at a loss as to how to proceed.

Should I replace the water pump next?

Any advice would be greatly appreciated.

Thanks in advance.

rworegon

What engine?
Under what conditions does it overheat?
What does the oil look like?
What does the exhaust look like after the engine is fully warmed up?
What is the condition of the coolant and radiator?
Can you see coolant circulating through the radiator?
Is the fan clutch working properly?
How many times has this overheat condition occurred? You may have done head/block damage.

desertrat666

rworegon thanks for responding.

It's a 3.4 V6 with about 275,000 miles on it.

The oil looks clear not milky and there is no white exhaust after it warms up so I think the head gaskets are ok.

The only clue is the steam blowing out the radiator overflow hose.

I am wondering if the OEM radiator is bad or maybe the water pump.

How would I diagnose whether the water pump is bad, it's not leaking.

rworegon

Did you replace the radiator cap?
How many miles on the WP? Are you due for a timing belt/WP change?
Have you done the fan clutch diagnosis? There are threads here on that issue.

Doubtful that a new radiator is bad.

Again, under what driving conditions and outside air temp is this occurring?

vital22re

iTrader: (2)

Did you place the jiggle valve to the 6 o'clock position? did you properly fill the the block then the radiator? Or lift the front end up and disconnect a heater hose to bleed out the air as you filled the system? Is your fan clutch properly working?

desertrat666

Thank you very much to everyone that has responded, much appreciated.

rworegon>> Did you replace the radiator cap?
rworegon>> How many miles on the WP? Are you due for a timing belt/WP change?
rworegon>> Have you done the fan clutch diagnosis? There are threads here on that issue.
rworegon>> Again, under what driving conditions and outside air temp is this occurring?

I did not replace the radiator cap and it is the original, I will pickup a new one today.

The WP is original (275,000 miles). I do not see any leakage on the WP and I can't hear any unusual sound coming from it. I am not seeing any circulation in the radiator if I remove the cap and bring the vehicle up to normal operating temps. The top hose gets very hot (as does the radiator) and the bottom hose remains cool. I think I am getting close to due on changing the timing belt. I have had major services performed at about every 100,000 miles specifically having the timing belt replaced.

I will test the fan clutch today.

The operating conditions that cause the vehicle to overheat are:
1. Starting the vehicle and letting it idle for a period of 15 minutes.
2. Starting the vehicle and then driving it for a couple of miles.

vital22re>> Did you place the jiggle valve to the 6 o'clock position? did you properly fill vital22re>> the the block then the radiator? Or lift the front end up and disconnect a vital22re>> heater hose to bleed out the air as you filled the system? Is your fan clutch vital22re>> properly working?

When I pulled the thermostat I viewed where the jiggle valve was and it was at 12 o'clock, so I installed the new one the same way. The thermostat that was replaced is the original and as it turns out was not bad. I tested it in boiling water and it opened at exactly 195% F.

I did not lift the front end and disconnect the heater feeder hose when when I refilled the radiator. I did try to get the radiator to burp by filling the overflow res and radiator and bringing it up to normal operating temp but that did not work. The heater fan is shot (sort of works) and bringing the vehicle up to normal operating temp does not blow any heat out the vents.

What started this whole ordeal was original radiator cracked on the plastic top plate so I replaced it thinking the radiator was just old. I am now thinking something caused the radiator to get so hot that it eventually cracked and that was the real problem to begin with.

Thanks again for the help.

rworegon

Congrats on 275K miles on the WP without leaks, but I wonder if it has any impeller blades left?

It's time to treat the rig to http://www.ebay.com/itm/Toyota-TIMIN...17wt_674"]this.

You will not beat this price and many of us buy from him.

The FSM (Factory Service Manual) specifies jiggle valve at 6pm for the 5vz-fe 3.4L engine.

https://www.yotatech.com/forums/f2/5...easure-249481/
https://www.yotatech.com/forums/f2/3...dition-261446/ See post #10.
https://www.yotatech.com/forums/f2/n...review-247545/

desertrat666

rworegon I think you're right, it's time to replace those components. Unfortunately my current living situation relegates me to shade tree mechanics as I probably don't have some of the tools (had to sell them off) and no garage. As much as I hate having other people work on my vehicles I might have to suck it up and have the dealer perform the work, uggggh. Thank you very much for your help.

rworegon

I hear ya'. Add your location to your profile and another member may be willing to help you out. Or, you might find a local mechanic that would install the kit above for you.

About the only thing the job takes other than standard metric sockets is a 250 ft-lb torque wrench (can often rent/loan from local parts store) and a crank holding tool that can be made for cheap. Oh, and maybe a scraper to get the old WP gasket off the WP/block mating surface.

Check out the timing belt tutorial in the last link in post 7.

desertrat666

woohoo!

I went out to check the fan clutch, which is good, and I noticed the OF res was empty (it was full when I left it last night).

Evidently when the engine block and radiator cooled the radiator burped and sucked all the fluid out of the OF res.

Running like a champ now.

rworegon will be buying the kit soon and hopefully in a place with a garage when the WP finally goes.

Thanks for the help.

rworegon

Welcome. Glad you are back to running good.