lj78 engine still overheating

[JGarl]

Hey guys, a few months ago I picked up a lj78 that had the head replaced but was still overheating. Since the previous owner couldn't figure out the issue I was going into this kind of blind. so after picking it up I dropped it off at the mechanic and had the coolant system checked over, nothing stood out to them so I took it for a drive to try and get a feel for the symptoms of this overheating.

The things I noticed are: the engine took a long time to get up to operating temp(stock temp gauge), the heater was only working sometimes and very briefly, before the temp gauge got too close to the red I stopped to lift the hood and the overflow tank was bubbling and overflowing. I then dropped the truck back at the mechanics and had a full coolant system flush and a new thermostat installed.

after getting fresh coolant and a new thermostat put in I took it for another drive, this time the engine temp made its way up to operating temp and never went past that, but once I stopped again the overflow tank was bubbling and overflowing again.

things to mention are there is no smell of burning coolant, no white smoke, checked the oil and no sign of coolant in oil, the engine seems to run great with no issues, other then the bubbling overflow tank.

is it just air still in the system? or did someone screw up the head install?

any insight on what direction to go next would be appreciated thanks

 

[GTSSportCoupe]

Sounds to me like there is a good chance the new head has been cracked already. The bubbling/overflowing reservoir is usually a sure sign. I've got my engine too hot a few times, but NEVER had bubbling or overflow in the reservoir.

There is a slim chance that the system has just not been bled properly and there is still air in it that is being pushed out when it warms up. After a couple cycles of driving the bubbling will stop in that case.

On an aside, try to never let the temp get over 1/2 on the factory gauge. After this point, localized boiling occurs in the head, creating the hot spots which eventually crack the head. Certainly by the time the gauge is at 3/4, you are well into the danger zone on these engines.

When you do get this problem sorted out, and if you are interested in keeping your LJ, you should consider going to Evans waterless coolant. It doesn't boil until 375F, and is the perfect solution to the head problems on these engines.

 

[JGarl]

ya I only got it over half that once, but I do find it odd that since my coolant was changed and the new thermostat was installed the factory gauge doesn't seem to be showing any overheating at all. and I realize this gauge is not very accurate but its acting completely different then it was previously. so if the head is cracked again, any way to confirm without taking it off? is it possible its a head gasket problem instead of the head? installed incorrectly?

 

[GTSSportCoupe]

ya I only got it over half that once, but I do find it odd that since my coolant was changed and the new thermostat was installed the factory gauge doesn't seem to be showing any overheating at all. and I realize this gauge is not very accurate but its acting completely different then it was previously. so if the head is cracked again, any way to confirm without taking it off? is it possible its a head gasket problem instead of the head? installed incorrectly?

Sounds like the old thermostat was not working correctly at all. Unfortunately, that may have caused some serious problems if the previous owner did not keep an eye on the temperatures. The heater not working part may have been because it was full of air/combustion gasses.

I think there are a few ways to diagnose a cracked head or bad head gasket on these. I have not been through it myself, so I'm just repeating what I've read. Basically though, I think you can have the system pressure tested. I think it is also possible to check for combustion gasses present in the coolant (carbon dioxide/monoxide). Do some searching on the forums here, and also check out http://www.toyotasurf.asn.au/forum/viewforum.php?f=6&sid=9923119de91dcad1eb3bc286ad4b8195 . The Hilux Surf has the same 2LTE engine, and there is a lot more discussion about it on the surf forums than there is here on mud. Also, it's rare with these engines from what I've seen that this sort of problem is just the head gasket. Usually it is the head.

 

[VI Cruzer]

Hey guys, I had been having the overflow tank filling problem to a lesser degree going on 2 years. I recently had the truck in for a timing belt and they found that my radiator was in bad shape. The local rad shop re-cored it and since I got it back, it's like a different truck, well cooling wise anyway. I still drive it very head safe, but thought you may just have lousy flow through the rad. I do plan to go with the Evans, I think that will be very good.

 

[JGarl]

well i think I'm just going to take the advice of a lot of people on the internet and ditch this engine, I'm currently looking for a 22re or maybe the 3.4l anyone know if these will mount up to the auto tran? I've looked around but a lot of this info is very scattered

 

[GTSSportCoupe]

well i think I'm just going to take the advice of a lot of people on the internet and ditch this engine, I'm currently looking for a 22re or maybe the 3.4l anyone know if these will mount up to the auto tran? I've looked around but a lot of this info is very scattered

Is yours manual or auto transmission? If auto, there are many Toyota engines that can be used. The 1UZFE 4.0l V8 from LS400 is probably the most popular gas engine that people put into the Prado (many in New Zealand). 22RE would be really under powered. 5VZFE (3.4l you mentioned) would be decent. I think mechanically all these are pretty *easy* to put in. It's the electrical that will be challenging...

Here is how the 1UZ looks in a Prado (good):

 

[JGarl]

ya I've seen all the info on the 1uzfe, but the biggest issues I've seen is with the auto tran(which i have) doesn't seem to shift like stock, or is there a way to make it run like stock?

 

[GTSSportCoupe]

ya I've seen all the info on the 1uzfe, but the biggest issues I've seen is with the auto tran(which i have) doesn't seem to shift like stock, or is there a way to make it run like stock?

That'll be the challenge no matter what engine you swap in. However, many of the swappable engines are connected to A34X transmissions as well. So I don't see why it is not possible to have the new ECU control your Prado A343F transmission. For example, the LS400 uses the A341E transmission. Basically the same as the A343F minus the 4wd stuff. *Just* a matter of adapting the wiring.

I think you can also buy electronics from New Zealand that guys make specifically for this purpose that allow you to manually shift the auto.

 

[Diesel Cruiserman]

Nother sad day in the life of the 2LTE..

We did the 3L and added the turbo, the engine did not survive to many years with a turbo installed..I thought it had a fighting chance.

However we did not change out the rad or had it cleaned? We never addressed the transmission, shifted way to early..

We were pretty green when we did this swap almost 10 years ago.

Rob

 

[JGarl]

That'll be the challenge no matter what engine you swap in. However, many of the swappable engines are connected to A34X transmissions as well. So I don't see why it is not possible to have the new ECU control your Prado A343F transmission. For example, the LS400 uses the A341E transmission. Basically the same as the A343F minus the 4wd stuff. *Just* a matter of adapting the wiring.

I think you can also buy electronics from New Zealand that guys make specifically for this purpose that allow you to manually shift the auto.

anyone know an electronic wiz in ontario that could sort all that out? granted I need to find a motor now but once I'm ready for the swap ill need to find someone that could make this thing run as a stock setup

 

[GTSSportCoupe]

anyone know an electronic wiz in ontario that could sort all that out? granted I need to find a motor now but once I'm ready for the swap ill need to find someone that could make this thing run as a stock setup

That is the million dollar question.

It'll be relatively easy to find a shop that can do the mechanical end of things. It's the electrical end where it'll be hard to find someone who can do a good job. Personally, I'd contact this guy: http://www.tweakdperformance.com/services.html I've used his services before putting a japanese supercharged engine into my normally aspirated MR2. His custom harness was truly plug and play; and fired up perfectly first try. The guy is very talented, and does good work. He is also very experienced and has a good reputation.

If you go for this, make sure you buy a complete car with the 1UZFE, so you get ALL the pieces you need. Early 90's LS400's are perfect and cheap.

 

[JGarl]

That is the million dollar question.

It'll be relatively easy to find a shop that can do the mechanical end of things. It's the electrical end where it'll be hard to find someone who can do a good job. Personally, I'd contact this guy: http://www.tweakdperformance.com/services.html I've used his services before putting a japanese supercharged engine into my normally aspirated MR2. His custom harness was truly plug and play; and fired up perfectly first try. The guy is very talented, and does good work. He is also very experienced and has a good reputation.

If you go for this, make sure you buy a complete car with the 1UZFE, so you get ALL the pieces you need. Early 90's LS400's are perfect and cheap.

ok thanks a lot