3Y headgasket blown or cracked head. How do I tell?

[Ashh]

Hey guys,

my cousin is touring around Australia in a Townace and it's got all the symptoms of a blown headgasket. After doing a bit of research it seems these heads are prone to cracking as well?

I've offered to fix it for her, but I don't want to do it twice. Likewise I don't want her to fork out for a new head if it doesn't need one... (and ofcourse it can't stay off the road for too long). Is there any way to tell without dissassembling if it's just a blown headgasket or if the head is fubared?

Any experiences?

[Dazza]

The head might be corroded around a water jacket too. I would just take the head off and have a look. If she needs it to be back on the road the same day, it might be best to get a new head or an exchange one.

[Ashh]

I think the head is aluminium so corrosion *shouldn't* be a huge problem surely?

Is cracking easy to spot though? I thought you had to get a dye and penetrant type stuff.

[Ashh]

Ended up just buying a new head. They're pretty cheap.

[Dazza]

The head is aluminium and they do corrode. I have one in my shed that needs to be welded because of bad corrosion around a rear water gallery. The 4Y engines gave more headgasket problems than 3Y because they have a bigger bore size so the bore is closer to water galleries. Most heads crack between the valves if they are going to crack so it should be just a matter of scraping off the carbon and having a look. Brand new 3Y heads are not that expensive to buy if you need one. The earlier 3Y engines use a different head gasket to later models because the water galleries are in a different position in the heads, so you need to know what year the engine is before buying a head gasket. The 4Y head will fit on a 3Y engine if you use the 4Y head gasket which i think is the same as later 3Y.

[Ashh]

ah cheers Wish I'd seen this before I bought one. I have a TIG welder and if I'd known the problem areas I'd have just gone with that. Ah well.

I told them what model/year the car was so hopefully it's the right head. These engines seem to have a crack prone head... I've never seen a toyota where so many people have had to actually replace the head.

[Dazza]

I have never heard of a 3y engine cracking a head in a Hilux. It might be the design of the cooling system in vans that causes the problem. If the radiator is lower than the highest water passage in the head, then air pockets can get trapped in the head and cause cracks from hot spots if there is a slight leak in the cooling system. The RB30 engine in VL Commodores had this problem but the same engine in Skylines did not give any problems because of the height of the radiator.