Head gasket failure..or loose bolt?

Wow..excited to have got my first tundra! I purchased a 2002 Tundra TRD a couple weeks back. Body is in decent shape for being its age and being in Canada. No major rust, but some is starting in a few places. I got it pretty low as prices go here , knowing there was something going on with a coolant leak.


Before I get too far into the background here is my issue:

Head gasket leak symptoms. After removing the valve cover, I found a loose head bolt...literally totally out..might be others. Do I just tighten it up and call it a day, or pull the head and inspect/change gasket? I have to do the timing belt anyways. Exhaust manifolds will be a pain. Would probably be easier to undo at the down pipe and remove together and deal with getting them off out of the engine...if I go that route


Now for the back story...

Here was my issue/diagnosis: Could only drive it maybe 6-10 miles and it would get air in the coolant system and start to overheat. After some Inspection I could see that the coolant smelled like exhaust. Top it up...good for a little longer..then same thing. I did a pressure test on the cylinders....one seemed a bit low ..about 40psi under the rest...otherwise pretty even (I forget the psi now). I decided it looked like a head gasket failure and decided I would tear into it. I was planning to do the timing belt and water pump at the same time since the vehicle has about 270k km on it and I don't k ow any history.


Looking for thoughts from folks experienced with something like this. There was a fair bit of work removing everything to this point...so it's not just bolt it tight and try it out...probably 85% labour to head removal.

 

The right answer is to remove the head, check it and the block deck for flatness. Try to find the cause of the loose head bolt too, make sure the threads in the block are OK.

 

Picture as described.

 

Head bolts don't just get loose like that.

Pull the head, someone else already started to do that so you have no choice now. The symptoms require it too.

 

Thanks Landphil. As I am going through scenarios in my head...it seems like the right thing to do. Time to get under the truck and undo the manifold from the down pipes. Those head to manifold bolts look ugly to get to...and in rough shape..

 

Wonder how long that has been going on... Hows the wear on the upper cam shaft in that picture?

 

Jengel....I wasn't sure if maybe there was a common theme of loose head bolts on these motors. Did come across one other post from another site with a similar issue...but doesn't seem to be common from what I could tell.
I think these are torque to yield bolts on these heads...would need new ones anyways I think.

 

Linwozzle it doesn't seem worse then the others....hard to tell at this point. I'll be checking my it out.

To take the heads off I assume cams come out next...only way to get at those bolts..

 

Timing belt....seen better days too. Probably original

 

Holy shit

 

That might be the worst I have ever seen. Lucky you caught it in time.

 

Yeah...as soon as I removed the cover and seen that belt my jaw dropped. It might be a blessing in disguise that I had to get into this right away...because I'm not sure that belt would have lasted too much longer ..

 

Any recommendations on HG brand? Rockauto sells an ITM or Enginetech engine gasket set. I see Fel-Pro has two types.of JG options. One is an "updated design" whatever that means. Reviews seem to be all over the place on ITM, not much on the other. I do t see a full Fel-Pro engine kit...so was thinking buying the ITM kit and a set of "Updated Design" Fel-Pro HG's.

 

Oem Toyota is hard to beat. The MLS gasket is far superior. You can buy a whole top end gasket kit for 300-400 bucks usually. YOU HAVE TO MAKE SURE THE HEAD AND BLOCK ARE TRUE. If they’re warped the mls will not seal

 

this kit has the valve seals, head gaskets, intake gaskets, cam seals, valve cover gaskets, the rubber washers for the valve covers, throttle gasket, etc for 316 bucks. (This is for an 05, you would need to look for your year)
https://parts.sparkstoyota.com/p/To...--Engine-Valve-Grind/62988584/041120F030.html

 

Thanks folks! I'll post some more when I remove the head today.
Another burning question I have. Do I do the passenger side while I'm in this? I'm leaning towards yes since I don't know the cause and I'm this far in it...would be nice to know the top end has been done.

 

I would say 100 percent yes.

 

What do most folks use for checking flatness?. Tolerance is tight so grabbing my aluminum level or that steel bar leaning against the wall doesn't sound like a good plan lol.
Just sitting here thinking of what I could use. I'm sure there will be some creative ideas out there.

 

This is the simple answer...lol

 

We'll...starting to rethink removing the head after 2 hours of trying to remove the exhaust manifold from the head and/or the downpipe it's a no go. Option is to cut it apart and replace the down pipe and cat. I'm now leaning towards torquing up the bolts and seeing what happens....otherwise some big money will be spent on a $3000 shop truck

 

We'll...managed to snap off 2 of the three studs at the manifold downpipe flange...and u did the one last but. I can handle that...if the work to replace studs issue to much work....I may try and look for a set of pacesetter headers. .....just after I complained about spending too much...

 

Ok...question for you 2UZFE experienced folks. I'm at the point of removing the camshafts. Xmas are positioned so the dots at the back are lined up. I Had the balancer at zero and both timing gear pulleys were on the marks before removal of belt and going deeper. Anyways...my issue is that I am supposed to use a 6mm bolt to hold the two gears together. The holes between the gears are lot lined up...I'm wondering if they were supposed to be and as suspected...someone who has no clue what they are doing were in here allready. I'll try and upload some pics. Can I just remove them and then I'll have to realign the gears when I reinstall? Not sure how tough that spring is...or what the scoop is there

 

Appreciate any feedback. I'm doing some searches on the forum to see what camshaft install removal I do I can find as I type this ..

You can see the bolt hole of the thin outer gear is at about 9 o'clock using the base of the head as horizon. The thicker gear you can see the bolt hole around 6 o'clock.

 

i would check to see if ARP makes a head stud kit , that’s what I would use instead of new torque to yield bolts . And I’d go with factory OEM gaskets , seals, water pump , idler and tensioner . Take the heads to a machine shop you trust have them checked and pressure tested .

 

55kcement, for the time ng belt/water pump kit I will be ordering off RockAuto for the Aisin kit. Aisin is the manufacturer for Toyota and is the exact same thing, just without the dealer markup. Good idea on studs. I'll check it out. I am going to check the heads for flatness somehow. If they need to be surfaced I can flatten them myself depending how bad they are. I have taken a few thousanths off aluminum LS heads using a sealed unit from a window(glass) with glued down sand paper. Took about 30-45 min but worked well.

 

I would not recommend doing the resurfacing yourself without the proper equipment, spend the couple hundred bucks and take them to a machine shop , it’s ridiculous to take all the time involved plus buying the parts and then take a short cut like that possibly compromising the whole job .

 

I would check the service manual to see if the heads and block can even be resurfaced. The 4.0v6 cannot be milled according to the toyota service manual. If it’s still within spec I would just leave it, or get a new engine.

 

Very good point specter , maybe you can find a lower miles used engine ?? And just put a new timing belt and pump on it ??

 

I'll look up the head and block specs. I'm not worried about that part. Right now I am trying to find out what happens when I remove the cams without the service bolt seeing as they are not lined up. My budget for this repair is about $1000cad...so $700 us. I'll do what I can with that amount.

 

Well may the force be with you !