Head gasket repair vs engine swap

What is “average Joe?” You got mechanically inclined, and know what you doing to do it. Also, make the time, and paticence, have the confidence to do the job right.

 

I did the head gaskets on my 4.0 V6 in 2022 at 295k. I just passed 330k. I'm not a mechanic but I'm mechanically inclined or at least think so.

Here is a link to the thread here when I did mine. Btw, you can confirm the leak by pressure testing the cooling system and then inspecting the cylinders using a borescope.

4.0L V6 with bad head gasket (repair or replace?)

 

I did my head gaskets a while back, and I learned my lessons a long time ago, always have the head surfaced. I had mine checked and sure enough one was not straight. its a lot of work to redo for the sake of 100$ to have them machined. so while your searching do as the others advised, dump some head gasket repair magic in it, the worst thing to happen would be it does not work. A good friend has a 3.4 4runner, 550,000kms on it tried the "magic" 2yrs later still going (daily driven)

 

I'm surprised the labor to replace head gaskets is as much as a used engine + labor to swap. That seems crazy to me. I'd personally swap the head gaskets myself but I know it's a big job and most people go to a shop for that.

 

2003 (4Runner)-2005 1GR-FE motors are known to have faulty head gaskets. Unfortunately, a common and well-documented issue. Toyota changed the head gasket design in mid-2006. This one is right on time with the rest (most happen around 200k). If the motor wasn't overheated and it hasn't been run long with the faulty head gasket then just replacing the head gaskets may be a consideration. Because of the year in question, though, I would make sure to have both head gaskets replaced which might be more expensive, and certainly more complex (multi-chain driven DOHC, VVT-i, etc.), than just finding and installing a newer motor.

If you do have the head gaskets replaced, make sure your mechanic knows that 1GR-FE's are sensitive to any head resurfacing. If done improperly, the timing will be off and it will never run right if the head is milled/re-surfaced without use of the corresponding thicker head gasket. Example: if heads are milled .005", you must use a head gasket that's .005" thicker.

 

If it were my motor, I'd replace the head gaskets (both) and not consider a different motor unless the current mileage was prohibitive which is kind of the case with the op. Even at that mileage I'd be hesitant to swap because (in my case) it's a known good motor and most used 4.0s are over 100K mi, sometimes you can find a low mileage doner but it's getting more difficult by the day. Getting a later year motor is no guarantee it's HGs will last the life of the new motor. A replacement would need to have pretty desirable mileage to ditch a known good motor. Bad HGs with no other known issues and no overheating is still a good motor IMO esp if I was the person who put the last 100K on it.

Have the heads reworked, change out the typical wear items and the coolant pipe and the 300Kmi will likely run better then the junkyard replacement and still be cheaper overall, I'd also have piece of mind that you wouldn't have with the other motor. Bottom ends on these motors are stout.

 

Not sure where your from but another option...
Example, in San Diego theres still a handful of reputable engine machine shops / rebuilders locally....
You can always pull your current engine & have it refreshed / rebuilt....
Need to do your DD & evaluate cost of all your options....