Toyota/Lexus A25A-FKS Teardown… It’s COMPLETELY SEIZED! Will this become a Common Problem?

On Toyota forums the electric A25A water pump has been failing all over the place at between 50,000-130,000 miles. Ditto the electric thermostat and coolant by-pass valve. Bottom line: the electrified cooling system of the A25A is its Achilles heel. The rest of the motor has lasted up to 502,000 miles with 4,000 mile engine oil changes. Owners need to occasionally scan the temperature gauge and be ready to call a tow truck BEFORE the gauge gets up into the RED zone.

A25A-fks tear-downs are hard to come by, great video and thanks for bringing us along!

I mean yeah, if owner was driving with failed water pump after getting check engine light - this is certain outcome. That been said I think this is a first water pump I ever saw on A25A-FKS to ever fail. I think owner should buy a lottery ticket, he might win fortune.

Interesting that the successor to the A25A, the turbocharged T24A-FTS, uses a conventional belt driven mechanical water pump.

"Now I should be able to rotate the crank" proceeds to smash the pistons

Nice job on the video. I am so impressed with Toyota's engine designs. It's no wonder they are so reliable.

My 2022 Venza has a A25A-FXS hybrid version . Glad to see a tear down of this engine . Mine has no serp belt for alt or ac , as they are electric driven . And no place for a starter either.

Still can''t get how variable discharge oil pump is controlled here. Yes, there's a short chain connecting crankshaft and oil pump, but it is just a driver. Well, there's something like a chamber in block, where they put pressure sensor. The pressure value comes to ECU. However, which way the ECU says to oil pump "more , less"? In other words, how does ECU affect the oil pump capacity?

Noticed that main bearing oil clearance by engine service manual are not equal. For example, 1st, 2nd, 4th, 5th - 0,014 mm standard value. 3rd - 0,020 mm standard value. What could be a reason for that? What's wrong with 3rd one?

Pistons did move with a bit of persuasion...

Why can't the engine shut itself down when it severely overheats or better still, when the ECU detects that the pump is no longer drawing current?

I’ve never heard of a problem with the Electrical water pump ever!on A25A.

All we can do is guess/speculate what caused this mishap. I would have like to have seen the oil that was drained initially at the dealership. Ive read forums where those in the know speak of the EGR cooler you removed somehow allowing water/condensation into the oil on both dynamic force A25a and M20 engines. How much water is unknown but ive read threads where the engine oil appears frothy with water which would not help lubricate the engine bearings, pistons ect. Not a fan of electric water pump either with its historically short lifespan. My 08 Civic Si purchased new has its origional water pump at 16 years of age. Ive been researching this engine for some time now as i do all my own repairs and considered (past tense) purchasing one. PCV valve location is a PITA for example and not easily accessable as with most engines. EGR is overly complex. Water pump failure seems plausible in this case. Surprised how dirty intake valves were knowing this engine has port injectors as well as direct. Chain guides appear all plastic versus honda's metal and plastic design. Plastic bits all about combined with heat and time will fail eventually. Not my cup if tea.

I noticed a huge tooth gear on crankshaft which supposed to be a driver for balancing unit. My question is, is crankshaft, connecting rods and pistons, this group in whole so much made unbalanced, so it forced Toyota engineers to implement pretty heavy tooth gear and balancing unit? In order to get rid of engine vibration. Vibration vs Weigth (fuel consumption). What do you think about?

Hi there, there's a need in some theory. 🙂 you told us that proper oil for A25A-FKS is exact 0w-16 grade (and even 0w-8, e.g. Corolla 2024), because this engine itself was designed for low viscosity oils. To be exact these engines line, I mean "dynamic force". Could you point out on those particular engine units which will suffer if owner use, say, 5w-30 oil. And please explain. Why? Also could you share oil clearance for mentioned above engine? -main bearings standard value and acceptable value; -connection rod bearings standard value and acceptable value; Thanks in advance!

how many miles was this motor?

hello jcap