Toyota LC80: 1HD-FT 24-valve cylinder head cracking (pre-1998 head casting)

The 1HD-FT is the 4.2 twenty-four-valve turbo diesel fitted to the HDJ80 from 1995, and its defining weakness is the cylinder head itself cracking — typically between cylinders or through into a valve seat. Any overheating event, and any extra heat from a turned-up injection pump or a bigger turbo, sharply raises the risk. Toyota made a running change in 1998 to a revised head casting and an updated head gasket, released under bulletin TSB-98-04, which means an 80 Series still on its original head has the casting that cracks. A cracked head pushes combustion gas into the coolant and coolant into the cylinders: you get bubbling in the overflow bottle, coolant disappearing with no puddle underneath, sweet white smoke that will not clear, and eventually a hydraulically locked engine. This is not a head-gasket-and-hope job; the head has to come off and be replaced or properly repaired, and it is the single biggest financial risk on this model.

• Steady stream of bubbles rising in the coolant overflow bottle with the engine warm and running
• Coolant level dropping with no visible leak or puddle
• White smoke from the exhaust that keeps coming once warm and smells sweet rather than oily
• Temperature gauge creeping up on a long climb or while towing
• Creamy mayonnaise-like film under the oil filler cap or on the dipstick
• Heater blows cool because the system is full of gas

1. 1

   Get to the vehicle before the seller has warmed it up and put your hand on the bonnet when you arrive to be sure it is stone cold.

2. 2

   Watch the exhaust for the first two minutes: a diesel puffs a little white on a cold morning and clears, but white smoke still pouring out once it is warm, with a sweet smell rather than an oily one, is coolant going through the engine.

3. 3

   With it running and warm, look into the coolant expansion tank and watch the surface for a steady stream of bubbles arriving, and for an oil sheen or brown scum on top.

4. 4

   Check the underside of the oil filler cap and the dipstick for a creamy mayonnaise film.

5. 5

   On the test drive put the heater on full hot, work the engine up a long hill, and watch the temperature gauge for any climb away from its normal position, then check the coolant again once it has cooled.

6. 6

   Ask directly whether the cylinder head has ever been replaced or skimmed and ask for the invoice, because a head fitted from 1998 onwards is the revised casting Toyota released under TSB-98-04 and is the one you want.

7. 7

   Ask whether the engine has ever overheated, how often the coolant has been changed, and whether the injection pump has been turned up or a bigger turbo fitted, since both add heat this head does not tolerate.

8. 8

   If a workshop inspection is possible: ask for a combustion-gas test on the coolant and a compression check across all six cylinders before you commit.

Parts involved: Cylinder head.

$4,500 to $9,500 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the cylinder head ever been replaced or skimmed, and do you have the invoice?”
• “If the head was replaced, was it the later revised casting?”
• “Has the engine ever overheated, even once?”
• “Has the injection pump been turned up or a larger turbo fitted?”
• “How often does it need coolant topped up between services?”

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

• EngineCode — 'Toyota 1HD-FT Engine Review: HP, Torque, Common Issues' (cylinder head cracking between cylinders and into valve seats; 1998 revised head casting and updated gasket under TSB-98-04; HDJ80 application 1995-1997)
• IH8MUD forum — '1hdft and 1hdfte cylinder head differances?' thread (owners fitting the later head design to escape the cracking problem)
• Offroad80s forum — 'Do 1HD-T's crack Heads' thread