As a life long 3FE enthusiast, I’m really not concerned with the durability of my motor. I figure as long as I have some oil in there sloshing about she’ll run forever. However, my brother does own a 1997 LX450 so I am curious about the causes of head gasket failure on these motors.
Has anyone done a study or a poll to find out if, on those with documented HG failures, were the commonly overlooked items, well, overlooked? For example, how many HG failure cases never replaced the fan clutch since owning the vehicle?
John, as a proud owner of the 3FE I read and examine the pics posted up on HG threads closely also. It appears to me that the weak link seems to be the headgasket design itself more so than heat. There seems to be alot of failures and deformation at the fire ring(s), especially the #6. IIRC The replacement gaskets are of a different better design.
I am sure that heat can also be a contributing factor and exasperate the head gasket failure but it seems to me that the design is the main culprit.
I understand, but there are trucks with failures and trucks without. Probably many many more without as far as I can tell. One of the first things I told my brother to do after 100K miles was to change the fan clutch. The Toyota dealership didn't want to, he didn't want to do it, everyone said it was a waste of money. Long story short, he replaced it (I kept hounding him). Now all of a sudden his AC is working "so much better", the "sound of the motor is so much louder" and it "feels better".
All that with no change in the temperature gauge. Now we all know that the stock gauge is useless, we all know that the lifespan of a fan clutch is 100K miles or so, and we all know that there is the POSSIBILITY of HG failure do to whatever reason.
Do a search and mod that Fan Clutch. If it is new, it is adjustable and the oil can be changed. The factory setting can be all over the place. Also mod the temp gauge. Both are really inexpensive.
IMO these are the two most important things to do to a 93-97 cruiser. Third would be Landtanks MAF housing for 95to 97 cruisers.
The truck will run much better/smoother after these mods.
If my headgasket blows, I will eat my words that the fan clutch is not one of the main issues of 1FZ headgasket failure.
I think the temp gauge mod is #1 on these trucks. With that big dead spot you could be running around at elevated temps and not know it. While these elevated temps should be ok, when combined with the original HG design I think it's not in the best interest of the engine.
One main overlooked item is the temp gauge. I agree with what Landtank is saying. If your radiator is dirty or clogged and or the fan clutch is not working properlly you may drive around hot without knowing.
Jon the pattern is not easy to track. I have sold ~40 valvegrind sets in the past 12 months and many were for PM replacement, some for a rainy day and some for failure replacement. I should also say that my client base does not reflect the national sales history. According to Partsvoice there are only 18 dealers in the country that stock the gasket set and I normally keep 4 on the shelf.
Absolutely over-heating one guartantees that the head will move enough to get the #6 fire ring to fail.
My informal tracking tells me that the majority of failures are seen in 95-7 vehicles. Part of that could be the fact that there were more of those built versus the 93-94. I believe that most all are destined to fail at some point. The trick appers to be guessing the point. Mine is at 152,000 miles with the original gasket and over half of that mileage has been supercharged. Mine shows no symptoms at this point. There are several known 93-94 examples with 200+ thousand miles and original gaskets. I do not know of a later truck that has gone that far.
My inspection of multiple failed gaskets shows almost every one failing at the back of the #6 fire ring. The ring gets "pulled" into the cylinder and it separates from the main body of the gasket thus allowing coolant to enter the #6 cylinder. The current revision of the factory replacement gasket has the metal that makes the fire ring extend all the way to the back of the gasket and it is captured by the rearmost head bolts, making the movement of the ring impossible.
I think if I had a 95-97 I would plan to replace the gasket at a time and place that was convienent to me and I would watch a 93-94 like a hawk for symptoms.
It's already been stated that the major underlying issue is the original gasket's design. Everything else just compounds that problem.
Talk with IdahoDoug. He insisted that the failures where due to poor maintenance and defiantly told people he was not going to have any issues. Then 3 HG jobs in about as many months and he's singing a different tune.
Look at LxTreme's truck. I think that guy believes there are expiration dates on the parts as he's changing stuff out that still looks new and his failed as well.
There is no magic bullet in avoiding the problem except doing the job correctly.
Well this just sucks. I know very little about the 1FZ-FE motor other than where the fuel goes and I'll give you one guess who's gonna be doing the HG on my brothers rig.
Just drive it like you stole it . I got mine with 95K on the clock with unknown maintenance , tossed a SC on it at 100K and Im at 140K at this time .
The gasket is from the factory . I changed the waterpump and fan clutch at the time of the S/C cause I was in there .
When it goes , Dans doggies will get fed ;p
I got mine with 95K on the clock with unknown maintenance , tossed a SC on it at 100K and Im at 140K at this time .