Do I need a "head" HJ75 with slight cracks in head (1 Viewer)

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Joined
May 8, 2011
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Location
Brentwood TN
Hi Mud dwellers ...

I need advice .. My HJ75 Overlanding rig is in pieces with a bad head gasket ... 2H - is it just the PreCUP

I have noticed slight fractures ... Is this a big issue .. Is this fixable

I only run this around 4 - 6 PSI so i don't put much boast through it.. I am trying to figure out if I continue with it or Drop an 6.0L LS in it ..

I need guidance and I do not have any friends that understand anything about Diesel Toyota's..

Please help.. I have no ideas where else to even get a new Head from with all the travel restrictions

Toyota 2H Head.jpg
 
Last edited:
What engine?
 
Take it to a machine shop. They may be able to repair it but doubtful. I’m parting out my 2H but haven’t cracked it open to look at the head.
 
If it's just the pre-cups that are cracked, I would think they can easily be replaced at a machine shop.

If the head it's self is cracked, you're in for a whole different can of worms. Not sure these heads are available anymore? If it is, it'll be an expensive deal no doubt.

Working a 2H with turbo is never going to end well. Indirect Injection (IDI) engines are not well suited to turbo. This is why Toyota made the direct injection (DI) 12HT as the turbo alternative to the normally aspirated 2H (and afterwards the 1HDT vs 1HZ) It's also why engines like the 2LT and 1KZT have overheating and head crack problems. Too much heat is lost from the pre-cup into coolant. Coolant has localized boiling around pre-cups, head overheats in spots and eventually cracks.

So, it all depends on your application. If you drive it easy, it could be fine. If you're heavily loaded or towing and doing big summits in summer, I'd be looking at either a direct injection turbo diesel, or a V8 gasser.
 
If it's just the pre-cups that are cracked, I would think they can easily be replaced at a machine shop.

If the head it's self is cracked, you're in for a whole different can of worms. Not sure these heads are available anymore? If it is, it'll be an expensive deal no doubt.

Working a 2H with turbo is never going to end well. Indirect Injection (IDI) engines are not well suited to turbo. This is why Toyota made the direct injection (DI) 12HT as the turbo alternative to the normally aspirated 2H (and afterwards the 1HDT vs 1HZ) It's also why engines like the 2LT and 1KZT have overheating and head crack problems. Too much heat is lost from the pre-cup into coolant. Coolant has localized boiling around pre-cups, head overheats in spots and eventually cracks.

So, it all depends on your application. If you drive it easy, it could be fine. If you're heavily loaded or towing and doing big summits in summer, I'd be looking at either a direct injection turbo diesel, or a V8 gasser.

Thank you.. Looks like it is just the PRE-CUP's so now i am on the hunt for them .. Issue is the big provider in Australia is in Melbourne and just told me that shipments to the US can take 2 months ... I think my wife Cadillac will be missing an engine if I have to wait 2 months.
 
try partsouq or other online shops. they ship within 3-5 days usually. I have heard that cracked pre-cups aren't necessarily bad, but I am not an expert. and pre-cups are replaceable, but don't know how to replace them. you need to get a 2H/12HT engine manual it will tell you how to remove and install these.
If you choose to keep the 2H you will need a EGT/Boost/separate water temp gauge. I fought a over heating 2H and what finally fixed the water temp was a custom aluminum radiator that was 2" longer at the bottom and had the upper hose intake extended about mid way inside the upper radiator header which forces the water to better cross flow since the factory radiator inlet/outlet are on the same side which isn't a ideal design. I would have your head checked for cracks, and I don't mean the cracks in the pre-cups. If your head is still good, then I would replace the pre-cups and install the head and do the mods I mentioned and just drive accordingly. Before I got the heating issue resolved my water temps would out climb the EGT's, after the new radiator and multiple block flushing and new thermostat, the EGT's then would out climb the water temps. I also had a front mount intercooler.
 
Ask the supplier if he can send it another way. Or try another supplier, the pre cups are not rare or hard to find.
 
Thank you.. Looks like it is just the PRE-CUP's so now i am on the hunt for them .. Issue is the big provider in Australia is in Melbourne and just told me that shipments to the US can take 2 months ... I think my wife Cadillac will be missing an engine if I have to wait 2 months.

I just had some small parts shipped from Queensland via Australian Post express. They were taken to the post office last Friday (9th) and were in customs in LA yesterday.
 
Thanks for all your help..

quick update new Pre-CUPs arrived.. took about 10 days from Queensland and 14 from South Australia.. I ended up buying two sets .. just incase one got stuck in shipping.. head is going back tomorrow ..

If anyone needs Pre cups i now have spares in California
 

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