2.9L Cracked Head(s)

[Paul Heydon]

I recently purchased an 87 Ford Bronco II with 360 000 Km. The body and interior are in mint shape but it has a bad automatic transmission. We are in the process of installing a manual transmission. I have an extra 1989 2.9L from a ranger with 180 000 Km if the engine does end up needing to be changed. No point swapping heads on such a high-mileage engine. The temperature does not go up much on the gauge. The temp also drops when I put on the heater which blows hot air. When we blocked the radiator with cardboard the temperature came up to the middle. The thermostat works as it opens when the truck reaches 195F. It still blows heat but the temperature gauge goes down. The engine runs really well but wondered if it might have a cracked head(s) from overheating at some point in its life. I know the 2.9's from 1988 and prior had weak heads. The coolant builds up pressure and moves through the engine. I was going to do a coolant pressure test to see if there is a leak in the system. Are there any other tests to see if I have a problem? Maybe a bad temperature sender? Any advice would be appreciated.

 

[Uncle Gump]

Google glove test for head gasket. Lots of info on it.

It doesn't really sound like a head gasket problem. They build a bunch of pressure and typically steam out the exhaust pretty good.

 

[Paul Heydon]

Thanks. Do they normally run cold? Maybe temperature sensor? Cheers.

 

[Uncle Gump]

I really don't think it's considered one of the cold blooded engines.

Might be best to do a little testing with a thermometer and a infrared temp gun.

 

[Paul Heydon]

Thanks. We put the temperature gun on the engine and it was 190-200f. The cold side of rad was 135f and hot side was 195-200f. Maybe everything is cool? I looked into the glove test and what a great diagnostic tool. I appreciate all your advice.

 

[XTC90BII]

I put a new heat sensor in my 1990 thinking it was bad because my heat gauge never gets above the "N" in normal. The new sensor made no difference. Blows a ton of hot air when I ask for it on cold days.

Dennis

 

[Paul Heydon]

Thanks to the both of you.

 

[Paul Heydon]

Hi Uncle Gump, the glove test and the coolant pressure test passed. The engine is good and I wanted to thank you for letting me know about the glove test. It’s awesome that you take the time to share your knowledge with the forum and I. We are going to be putting a M5OD transmission from a 2002 Ranger in this week. We got the engine running good so now more wrenching.

 

[Uncle Gump]

Hi Uncle Gump, the glove test and the coolant pressure test passed. The engine is good and I wanted to thank you for letting me know about the glove test. It’s awesome that you take the time to share your knowledge with the forum and I. We are going to be putting a M5OD transmission from a 2002 Ranger in this week. We got the engine running good so now more wrenching.

It's really a community effort. Everyone here enjoys these old trucks... we love to see them running around and usually try to help other members.

I'm sure you will find a way to help too... it's just how it works.