Hi there, in the process of changing out a Chain Tensioner on the front of my 4.0 SOHC engine. Since it looks like i have factory (possibly ) parts on, the bolts are pretty rusted. I managed to take out 1 bolt out of the thermostat housing in order to remove it. There are 3 bolts that hold the thermostat housing on. 1 I was able to remove ( amazingly ), the other one snapped off and the one in the back I had a hard time getting a proper angle on it with a universal so it is possibly stripped (rounded ) a bit.

Is there any easy way of taking out thermostat, or is there anything I can remove to get better room in there? Not sure where to go from here. I'd like to replace the tensioner however I do not want to destroy everything else to get it out.

Thanks for any tips

 

Good how-to here, on thermostat housing: How To Replace the Upper and Lower Thermostat Housing on a Ford 4.0L V6 SOHC Engine

But I assume you already took off the throttle body and that's about it for room.

There are damaged nut/bolt remover sockets, they dig into the head as you turn the socket, some have hex head so you can use a wrench on the socket part for extra leverage, get that one if possible.

Snapped off bolt is tough, how much of the bolt came out of the hole?
Do you think it snapped off flush to intake?

If not then after you get the other bolt out you may have to lift up the housing and cut the bolt off so you can get out the housing.

Spray some PB Blaster or similar penetrating oil down the broken bolt hole now, so it has a chance to "penetrate"
Hard to get out a broken bolt even with direct access, if its hidden under upper intake it will be a bear

 

Getting the thermostat housing off the 4.0 can be a real bitch.

I ended up in pretty much the same spot you're in; broke a bolt and struggling with the rear/pass side bolt. After you get all the hoses out of the way (and take the fitting with the three hose baths off the side of the intake) you can get to that rear bolt with the right combo of universals and extensions. If I remember correctly, I think I broke that bolt loose with a wrench, then backed it out with a socket.

As far as the broken bolt goes, do you have access to a welder? Is there enough of the bolt left to weld to? I finished getting the housing out, then welded the broken bolt back together (could also just weld a nut on the bolt), let it soak in penetrating oil, and then it backed right out. The combination of the heat from welding and the penetrating oil really loosened up any corrosion.

 

Yes i have access to a welder and I did take the throttle body off. I soaked it originally with penetrating oil however I still snapped a bolt sadly. These are some good tips, i will try them. Also the bolt that snapped, it snapped about 2 mm's below the Hex head.So if i manage to get the housing out there should be a lot of bolt left over. Yeah im a lil disappointed with how hard it is, i come from being a jeep owner and aside from the common broken bolts i've never been in a pickle like this.

Additionally, while i am at it , i noticed that my coolant is a bit brown and rusted. It is about 3/4's full. Does coolant go bad or could i have a gasket gone? Truck doesn't leak any antifreeze, im gonna flush it anyways. If it leaked I would see it by now ( lots of snow this way ).

 

Yes, coolant needs to be changed every 2 years or every 5 years depending on the type of coolant.

Silicate based coolant is usually Green color, it needs to be changed every 2 years

OAT(organic acid) based is usually Red/pink and needs to be changed every 5 years.
HOAT, yellow/gold, also 5 year change interval

But there is NO COLOR STANDARD for coolant, manufacturers can use any color they want

I only run silicate based(green) on older vehicles because it is less expensive and I know I will have to change water pump or hose or ?? before that 2 years is up, lol, pessimist.

When you are done with tensioner I would flush the system and replace coolant.



Because you have bolt shaft sticking out you probably won't be able to lift off lower housing, so yes a pickle
You may want to just cut the housing out to save as much bolt as possible to get it out, or hold up housing as high as possible and cut the upper part of bolt off to get housing out and still have a bit of the bolt sticking up.