• Advertisement

4JG2 Overheating and cooling troubles

Get help fixing your Isuzu from other club members

4JG2 Overheating and cooling troubles

Postby JuanMS » Fri Mar 27, 2020 9:23 am

Hi everyone! I have some problems with my 4JG2 engine. A few months ago i had to change the cylinder head gasket (done by a mechanic friend) but after a while it started to bubble in the water tank again, and a few days ago it overheated again :cry: My first impression was that there is compression in the water line again.
I have checked the truck with this mechanic friend of mine, and he think that the problem is not a compression leak because we took of the radiator cap and when i accelerate the engine it didn't pull water out. At that moment we discovered that when the motor is idling the water circulate fine, but if i accelerate it the water stop circulating at all until i stop accelerating it. So it has a water circulation problem, but i don't have any idea what can cause this. The radiator is clean, and the thermostat is new and i have tested it before put it on, there is no coolant leak because the level of it never got down.

Also, it is hard to start when the engine is hot (working temperature). When it is cold at the morning it turn on fine, but after riding i while and the temperature gets up it is very hard to start, like if it is heavy. I have checked the battery and it is not the problem, and i also have repaired the Starter. Now i am thinking that it is out of timing, that the fuel injection timing is improperly adjusted. In the manual say that it is also a possible cause of overheating and cooling troubles.

Thanks for your time and if anybody have any idea i'll appreciate it! :D
JuanMS
Isuzu Baby
 
Posts: 7
Joined: Wed Jan 22, 2020 11:09 pm
Age: 26
Country: Argentina
City: Buenos Aires
Vehicle: Isuzu Pick Up 3.1 TD 1998

Re: 4JG2 Overheating and cooling troubles

Postby geeves » Fri Mar 27, 2020 9:33 am

4jg2 engines are known to crack heads. Did you crack test the head when you did the gasket?
Sanding your knuckles before starting work can help. That way you cant skin them
User avatar
geeves
Site Admin
 
Posts: 8962
Joined: Sun May 10, 2009 1:36 pm
Location: Rangiora
Age: 63
Country: NZ
City: Rangiora
Vehicle: 94 bighorn 4jg2
2013 Subaru XV

Re: 4JG2 Overheating and cooling troubles

Postby JuanMS » Sat Mar 28, 2020 2:27 am

Hi geeves. No i didn't. I know now it was a mistake, but it is hard to find someone who does that job where i live. If i have to take off the head again it is the first thing i'll do.
But now i am confused with the water circulation problem. Do you think that a crack in the head can cause something like that?
JuanMS
Isuzu Baby
 
Posts: 7
Joined: Wed Jan 22, 2020 11:09 pm
Age: 26
Country: Argentina
City: Buenos Aires
Vehicle: Isuzu Pick Up 3.1 TD 1998

Re: 4JG2 Overheating and cooling troubles

Postby geeves » Sat Mar 28, 2020 6:54 am

A long time ago I had a Ford Escort (1300 4 cylinder petrol small saloon) which got a small leak in the head gasket. It was a cold morning and I drove 5km before it boiled vigorously. The radiator was stone cold. What had happened was bubbles under the thermostat stopped it opening so the engine never circulated water. Took the thermostat out on the side of the road and drove 500km home
Sanding your knuckles before starting work can help. That way you cant skin them
User avatar
geeves
Site Admin
 
Posts: 8962
Joined: Sun May 10, 2009 1:36 pm
Location: Rangiora
Age: 63
Country: NZ
City: Rangiora
Vehicle: 94 bighorn 4jg2
2013 Subaru XV

Re: 4JG2 Overheating and cooling troubles

Postby JuanMS » Sat Mar 28, 2020 9:19 am

Well, your commentary makes me remember that the radiator, after driving a while and the thermostat should be open, is half hot and half cold (at the top part of the radiator). The right part where the water from the thermostat hose comes is hot, but the left part of it (at the other side of the radiator cap) is cold
JuanMS
Isuzu Baby
 
Posts: 7
Joined: Wed Jan 22, 2020 11:09 pm
Age: 26
Country: Argentina
City: Buenos Aires
Vehicle: Isuzu Pick Up 3.1 TD 1998

Re: 4JG2 Overheating and cooling troubles

Postby geeves » Sat Mar 28, 2020 12:43 pm

Could have a blocked radiator as well
Sanding your knuckles before starting work can help. That way you cant skin them
User avatar
geeves
Site Admin
 
Posts: 8962
Joined: Sun May 10, 2009 1:36 pm
Location: Rangiora
Age: 63
Country: NZ
City: Rangiora
Vehicle: 94 bighorn 4jg2
2013 Subaru XV


Return to Engine

Who is online

Users browsing this forum: No registered users and 14 guests