4th Gen Engine Swap - Cooling System "How To"

Hello all,

I wanted to make a post to give back to the Prius community.

Back in 2020/2021 I was deep into the research for doing a 4th gen engine swap on my 3rd gen Prius. You guys and gals were a big help!

I've put about 25,000 miles on my car and it is continuing to count quickly! I am living full time in an RV now and traveling the US with the Prius at my side. Every day this car continues to pay for itself and all the work that went in to morphing it from the 3 year sitting "field find" that it was to the 4th gen engine & lithium battery reliability monster of a car that it is now.

I believe these 4th gen engine swaps provide so much value to these cars. I know many of us are busy fixing head gaskets, but I would most certainly consider knocking out a 4th gen engine swap to those of you with some wrenching abilities. I paid $1750 shipped for my 38k mile 2018 engine in 2020, however, prices have gone up now unfortunately. Nonetheless, still worth it in my opinion!

I timed myself on removal time for an engine on this car... One hour and 38 minutes. Essentially, if I have a motor sitting in front of me that is 100% prepared for drop in, I can have a car in and out of my garage in one day with an engine swap. Not to mention, much of the required steps are the same as a head gasket. Having also done a 3rd gen head gasket, I can personally swap engines faster. I hope this info is encouraging.

Here is a video I made detailing the cooling system of a 4th gen engine swap. I hope you find it useful. Others have documented the requirements, however, I believe what is shown in the video & left in the comments is as quick of a reference as one can find (5 minutes w/ little to no reading!).

Quick picture of the Prius in focus for fun!

 

Hi Tom,

Unsure of how many total miles have been logged in 3rd gen pri with 4th gen engines. However, all reports that I have seen show that the 4th gen motors are not having the same problems as the 3rd gens. Good to know, but the forum testing is all subjective at this point unfortunately. Time will tell, but regardless, it is nice knowing I've got the redesigned (updated) parts with an entire engine assembly that only had 38k miles on it.

Me personally, I have only put about 25k miles on my car since the swap. No head gasket issues, and the car burns 0 oil. Yet, with such low miles, the significance of this information is null in my opinion.

Your point is interesting regarding the number of miles that need to be put on the car to make any sort of pay off or true analysis of the effectiveness of such a swap. Unless this car gets into an accident this is a "workhorse" for my life. Going to work is cheaper, cross country trips are cheaper, vacation are cheaper, etc. I like my old cars with cheap taxes, insurance, and no car payment, so I'll probably just drive this car into the ground. Perhaps down the road I can update this thread with my 140k mile plus findings. I'd love to see this car reach 500k miles. Being it is roughly half way there already with no real signs of serious wear, I don't see any reason why it wouldn't. Time will tell!