Engine Head Gasket / Cracked Head Repair (Toyota 3.4L V6 5VZ-FE )

[19963.4lsr5]

I’ve done three sets of heads over the years and used YotaShop’s head replacement kit for all of them.

One important thing I learned over the years of wrenching is running a tap through the head bolt threads in the block to ensure the torque is correct.

 

[mtbtim]

No I did a full engine swap after the first blown HG and used nothing but OEM parts to replace since the engine I bought was used. And less than ten days into having the replacement engine in the HG blew out on the new engine so I'm thinking if there's a faulty component with the 3rd gen t4r and it's causing the HG to malfunction

The answer is the engine you got was a piece of crap. This is the risk you take buying used, even JDM that people profess is a great way to go. Any used engine you have no idea of its history is a crap shoot. The head gasket didn't blow 10 days after the install, the engine was already f*cked when you installed it.

 

[BigKat]

New Member - Stumped

PART 7


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New member here. Wont let me post so i had to reapond to this thread...Great site and have learned much and appreciate all of the information here. I have a very unique situation going on. 2002 T4R - 5vz - runs great, but losing coolant from reservoir. Has new radiator, water pump, thermostat, rad cap, oil cooler hoses, valve cover gasket, hoses, belts. No visible leaks anywhere. Losing about a qt per 50 miles. Cooling system pressure test - holds 15lbs for 30 mins no drop. Cold compression across all cylinders 210lbs+ except cly 5 at about 170. Leakdown test on cyl 5 is horrid. Losing about 75% through cyl 1 & 2 with cyl 5 at TDC. Very slight loss through intake. Retested multiple times to make sure #5 was on compression stroke. Any ideas? Can't put the coolant loss together with these results.

 

[mtbtim]

New member here. Wont let me post so i had to reapond to this thread...Great site and have learned much and appreciate all of the information here. I have a very unique situation going on. 2002 T4R - 5vz - runs great, but losing coolant from reservoir. Has new radiator, water pump, thermostat, rad cap, oil cooler hoses, valve cover gasket, hoses, belts. No visible leaks anywhere. Losing about a qt per 50 miles. Cooling system pressure test - holds 15lbs for 30 mins no drop. Cold compression across all cylinders 210lbs+ except cly 5 at about 170. Leakdown test on cyl 5 is horrid. Losing about 75% through cyl 1 & 2 with cyl 5 at TDC. Very slight loss through intake. Retested multiple times to make sure #5 was on compression stroke. Any ideas? Can't put the coolant loss together with these results.

Do a leak down test on Cylinder #5 again, but this time do it in conjunction with your cooling system pressure tester holding pressure on the cooling system. When you pressurize the cylinder, if the cooling system pressure tester gauge rises, you either have a cracked head or a head gasket issue. You can also leave pressure on the cooling system for longer than 30 minutes. Leave it overnight and use a borescope to look into cylinder 5 to see if coolant has pooled on top of the piston. I'm suspecting you have a cracked head. It's fairly common on these engine. Coolant doesn't just disappear like you're experiencing. if you haven't detected a leak anywhere, your engine has to be consuming it. Even if the leak was in the valley between the heads, the level would eventually spill out the backside of the engine and leave a puddle under your rig.

This video will show you exactly what I'm talking about. Good luck!

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[BigKat]

Will give this a shot. Thank you!

 

[JBurt]

First off, thank you for going through all the time and effort. Put your series together. I just got done watching all seven parts, and it was very thorough and very helpful.

It looks like I'm going to be tackling this job in the pretty immediate future. Mine is a 97, with a composite head gasket. Should I replace it with another composite, or go MLS 4runners?

 

[phattyduck]

First off, thank you for going through all the time and effort. Put your series together. I just got done watching all seven parts, and it was very thorough and very helpful.

It looks like I'm going to be tackling this job in the pretty immediate future. Mine is a 97, with a composite head gasket. Should I replace it with another composite, or go MLS 4runners?

There's a good reason why Toyota changed over to the MLS gasket in the later years of the 5vz... If your block and head finish is correct (smooth!), the MLS gasket will be better for sure.

-Charlie

 

[BuffaloBass]

surface finish!

and Charlie's IF is a REALLY BIG IF! Newer MLS gaskets are a bit pickier on sealing surface finish.

 

[JBurt]

That's what I thought the big issue might be. I'll have the head pressure tested and machined while they are off, but I don't want to pull the block to get it surfaced. I guess I'll find out once I get the heads off.