DCS

I've had this runner for almost a year. My home is a slightly colder climate than where the vehicle came from.

It seemed to shift fine last summer. This winter, it has wanted to "hunt" for overdrive. It seems to prefer staying in 3rd, and when in overdrive, will drop back into 3rd too easily. Some of the other shifts also seem rough every now and then.

I noticed yesterday that even driving up a 10-mile uphill road in 35? weather, the engine temp sensor never reaches the halfway point. It's always barely touching the little wavy lines on the left side of the dashboard thermometer display.

1 - is my engine running too cool?

2 - how many different thermostats are available for these engines?

3 - what's a good thermostat for 4000 mean elevation, 0-30? winters, and less-than-100? summers?

Also, my engine light came on recently, code 71 EGR. So i gotta deal with that. Does the EGR ever get stuck open, thereby continually bleeding exhaust into intake, thereby keeping engine too cool? My engine runs fine. Power is typical of 3.slow, and i have no stalling or starting problems. Could an EGR problem whack out the tranny shift algorithm?

I do have the link to the online shop-manual. My throttle cable linkage is correctly adjusted. My tranny fluid level is correct.

My plan of attack is as follows:

1 - determine if I am running too cool; like right on the edge of the O/D temperature threshhold. Maybe a hotter thermostat will fix this?

2 - test my 2 engine temp sensors, maybe one of them has failed.

3 - drop the tranny pan, change at least one of the solenoids. I found a link to buy all three for $160, link


4 - somewhere in there, gotta fix the EGR problem.

Thanks for any help or suggestions...

toyota_mdt_tech

I bet its a poor E17 ground in the front of the engine room wire harness. Also, water temp sensor in back of intake (single wire) could be bad or plugged coolant flow to it. The E17 is the most likely culprit.

Targetnut

, but it would make since to check the coolant temp first. A missing or stuck open thermostat would cause the same problem.

As far as a replacement part. I think the factory thermostat is 85deg C so I'd go with that

toyota_mdt_tech

You might be right. I was assuming his temp gauge was running mid way. This applies to all Toyotas. The gauge needs to be right int he middle, plus or minus only a smidge, anything else is overcooling or running warmer than norm. Get a factory thermostat only. Those darn aftermarket ones makes it impossible to drain your block when doing a simple radiator drain without removing the thermostat as it doesnt have the little "jiggler" valve in it. Get OE, far superior to even the best aftermarket ones.

DCS

Thanks for the info guys!

My temperature gauge is way shy of the "middle", even when working hard.

I do have a thermostat; it has the jiggler valve in it. I even replaced the o-ring on it because the new WP came with a new thermostat o-ring.

When I flushed, I added fresh water into the upper rad hose, with the lower hose removed over a bucket. I could see the thermostat cycling. Every now and then, it would dump hot fluid in the bucket. I added water in at the upper hose each time the thermostat dumped hot out the bottom hose.

Do thermostats wear out?

Do they have markings to tell what temperature opens them?

If the problem is not my thermostat, what else could get stuck open to cause an engine to run too cool?

THX!

olharleyman

definitaly go with oem thermo i used a aftermarket one and it leaked and would not heat up to proper operating temp

toyota_mdt_tech

Thermostats (OE anyway) will have the marking near the opening, but it will be in centigrade. I think it will be 88 or something like that. A great place to bookmark is http://www.worldwidemetric.com/metcal.htm for your conversions. As for overcooling, if its running midway, its dead on, but I have seen the RTV sealer peices get caught intot he thermostat openening or anything for that matter, then it overcools and never opens enough to release the debris which is stuck in the valve.