Engine Coolant indication

[ercoupe27]

I have a 1993 dolphin v-6 4 speed auto, that is well maintained. While driving in hot weather 95 oat the temp climbed into the red. I pulled over left it running , opened the hood expecting to see steam and over flow and there was none. I could put my hand on the top of the radiator, the fan was running and the coolant level in the radiator was slightly elevated. I squirted water in to the radiator and the guage came down a little but still indicting very hot. I then drove over the summit and the engine cooled off very quickly and I continued another 150 miles in high altitude and warm conditions with no further problems. She runs great and was getting good mileage after the temp spike. I am almost convinced that the problem might be in my sensor. Anyone have this problem?

[waiter]

Your probably OK, May next time your under the hood,install a new thermostat. You didn't say if you were running the Air Conditioner.

John Mc

88 Dolphin 4 Auto

[Boots]

Hi,

I have spent a fair amount of time considering the heating and cooling of my Toy and here are my thoughts. I recently lost a head gasket / engine failure and during the course of getting it fixed, I had three conversations with Toyota and others about heat related failures. On the internet chats, a head related failure on piston #6 is common, and usually the result of ongoing overheating issues, the result of this failure is almost always a significant rebuild.. On my last conversation with Toyota, the service manager specifically warned me (as handed me my reimbursement cheque for my engine failure repairs) that they would not cover any more engine repairs and that I would be very wise to flush and change my coolant regularly because of piston 1 & 6 overheating problems. The end message try not to overheat your engine and get your transmission oil changed (all of it) and regularly flush and replace your engine coolant. By the way, my engine rebuild was 3200.00 and was covered by a secret Toyota warranty plan (for certain year models).

I have had two friends who have problems similiar to yours with engine and transmission failures (on the V6) due to extended periods of overheating and poor/taxed cooling systems.

My course of action is to add two temperature sensors, the first is a head temperature guage (600 + F range) and a specially ordered VDO transmission temperature guage (150 - 400 F range) plus a special adapter to have the temperature sensor in line with the outbound transmission oil (to ensure accurate reading of the transmission oil) and finally I will consider a larger overall radiator in the future. The reason for each of these guages is of course to know the actual temperature of the engine's head casting, rather than guessing at it or having someone say to " don't worry ". The reason for the special transmission temperature guage and sensor setup is it gives you actual temperature (not the transmission's oil pan mix blend area, where hot oil is mixed with cooled return transmission oil) - the concern with oil transmission temperatures is that if the transmission oil is overheated (say 300 - 350 F) for a short period of time (say climbing up and over a summit) the transmission oil will break down and the protective ingredients are compromised. The end result is that the life of your transmission oil goes from 25000 miles to 3000 miles. You don't have to be a genius to figure out that if you are on an extended trip, you could easily rack up the mileage with a compromised fluid.

I looked into the cost of rebuilding my V6 transmission, and the general estimated is 2650.00 and a complete replacement if you can find one is 5100.00, the math is pretty straightforward.

On another note, others have commented on a new / different temperature controller and here is a quote from another website that might be of interest to you. I think their suggestions are a wise investment, for a small amount of money.

Here is what they have to say:

" Temperature gauge overshoot. It's a somewhat common problem on the 22r series motors. Installing the dual stage thermostat (part# 90916-03070) should alleviate the problem. "

Food for thought,

Brian

[Davidadro]

I agree with Waiter, a thermostat is inexpensive and easy to install. It could be beginning to get sticky, and a cheap fix to something that could cause an expensive one later. I would also check the wires to the sending unit to see if they are free of any heat retaining crud, oil or exposed wires shorting out against to block. The head gaskets of the V6 are prone to failure on some versions, and if you concerned or have not had the repair, check out this post by Boots, as Toyota paid for the replacement.

http://toyotamotorhome.org/forums/index.php?showtopic=5010&hl=

Good luck!