Seeking advice on buying a Prius v

Plenty of people like the AP200

 

The Toyota maintenance schedule has a group of inspections and a tire rotation at 5k intervals.



They will certainly do an oil change if you ask.

 

Yup, don't shoot the messenger.

 

An original gen3 head gasket is not the messenger, it is the villain as designed by Toyota engineers. Those same engineers redesigned the head gasket and an improved part or its Felpro equivalent would be in the op's car.

One thing that is indisputable about gen3 hg fails is the incomplete original black sealing layer of the metal head gasket erodes away allowing a seep of coolant into the cylinder. The revised head gasket has a complete black sealant layer.

Once a hg leak barely starts, over the first few months or even a year it only drips after an overnight cooldown of the engine. Sometimes it causes a misfire, severe rattle and shake; often it does not. The hg seals quickly once the engine is running. At first there are no codes but the shake is unmistakable. The parts cannon is fired. No detectable hydrocarbons in the coolant. No change of compression. No coolant in the oil. No observable coolant reservoir drop. New spark plugs often clear the symptoms for a week or two but do not fix it.

Traditional blown hg causes still apply such as overheating with warping or loose head bolts. But other triggers exist. Some have good reason to believe acidic coolant eats away at the head gasket sealing layer. Many advocate frequent coolant changes.

Carbon buildup from the original low tension rings (not the op's 2014 based on vin) will eventually generate preignition which is detected by the knock sensor but still occurs. Some gen3s get so carboned up the preignition (pinging) is clearly audible especially when combined with a low hybrid battery state of charge.

Overheating is the number one cause of head gasket failures in any aluminum engine. Aluminum engines warp. Overheating caused by the gen3 electric water pump often go unnoticed but can be brutal to the engine. Overheating due to exhaust heat exchanger leaks (which is vaporized through the exhaust) have occurred especially in early gen3s and gen4s.

Which is why I and others have an audible coolant temperature alarm set for 210f using a P10 with no history of network congestion. 248f is the vehicle alarm point and is a warning light only that often goes away quickly. Many with failed water pumps claim they never saw a warning.



If I had any sign of above normal coolant temperatures I would check the reservoir fill and coolant flow. Only once did the temperatures hit the 210f audible alarm, the reservoir cap was loose and was not allowing system pressurization.

I have seen many gen3 head gaskets fail at my local independent shop. He averages one per week over many years. A lot of the owners admit to driving after it overheated to get home. He gave up on hg jobs and went local rebuilt. He finally quit that approach and went locally inspected JDM replacements for a hg price.

if Toyota engineers or dealer master mechanics felt the gen3 egr was the root cause I would do more than frequent oil and coolant changes. Probably get a newer car. But so far we are good.