coolant leaking at temp sensor


91stranger

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So I noticed a coolant smell and sure enough there's coolant all over my engine bay on the passenger side and underneath but it is bone dry near the radiator cap. I couldn't find where it was leaking at first and I noticed my radiator was about half full and my overflow tank was still at the full mark where it always is. Also noticed coolant bubbling in the reservoir when I shut the truck off. I started thinking head gasket but I didn't have any of the other symptoms like milky oil or white smoke from the exhaust. I just changed my oil literally last weekend so my oil was still a nice clean oil color. So I finally was able to get it home and watch the engine run to see where the coolant was leaking and found it was spraying out from the engine temp sensor block that screws into the block. I can't tell if it had a crack in the fitting or if the hose was cracked and leaking. So I need to go to the junkyard and pull a full hose assembly and the fitting off a donor vehicle to see if this will fix my issue. I really hope its not something more serious but this was the only thing I could find leaking. Here is a pic showing the leak.
 

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ericbphoto

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Could try a new thermostat gasket first
 

91stranger

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T-stat was replaced last year which I know that doesn't mean its still good but it's bone dry at the t-stat. The leak is from the hose or the fitting.
 

91stranger

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wow no more comments on this. good thing I found answers on google. I figured I would have had a lot of responses about how to fix this but I guess I was wrong. Thank god for other ranger forums that did have the answer for this.
 

ericbphoto

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In your original post, it sounded like you found the leak and had a solid plan for repairing it. What more did you want? It’s just a coolant leak and you know where it is. There really wasn’t much to comment about.
 

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What eric said....

You said it was a hose or a fitting.
 

91stranger

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I was just wanting input from others if they had this same problem. When I googled it there were tons of people having the exact same issue but nothing on this site. Normally I can get good info and how-to's from folks on here but that wasn't the case. Seems like people can't help the people who need it but everyone and their brother can chime in when someone says "are winter tires going to help me in the snow?"...… like really?? So yes, I found the leak but it doesn't explain the other issues like the coolant reservoir bubbling and how the reservoir is never empty but my radiator will be half empty. I blew through the line going from the radiator to the coolant reservoir and there's no blockage. It doesn't explain why this happened since I never messed with that hose before. It doesn't tell me the best way to fix the problem. Someone on another forum said they moved the sensor to where the brass fitting is and just plugged the hose but that seems too redneck for my liking and I would consider myself a redneck.
 

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Well I can't offer a lot in the way of what to do to fix it, since I haven't dealt with this issue first hand, and that is, frankly, a craptastic picture. Even blown up I can't see anything useful.

If the coolant is genuinely coming out around the sensor threads I think I'd get a tube of thread sealer and pull the sensor to reseal it. If it is coming out at a hose the hose needs replaced, and/or a new clamp. Either of those can happen without you disturbing anything.


You coolant recovery tank was bubbling because the radiator was half empty. Air in the system will make it do that as the air tries to expand, and goes out the pressure relief on the cap.

Radiator cap seals the rad fill inlet, but it has a bi-directional pressure relief. As the engine heats up pressure in the system rises, and the coolant is allowed to flow out to the recovery tank. Since the system should still be sealed except for that one point, as the engine cools off the coolant begins to contract, creating a vacuum. This draws the coolant back into the radiator, replacing what effectively was allowed to boil out, and refilling it. When the integrity of the cooling system is compromised anywhere instead of drawing coolant back in from the tank it draws air in from the air. Since the coolant has already expanded to it's max limit you never push anymore out, and about halfway down the rad is where it will stop. But since air expands and contracts faster than liquids, it will follow the same rules. But when you have half a rad of air, instead of coolant the air, being lighter, will push out first. And as any kid with a straw and a cup of milk should know, if you push air to the bottom of a container of liquid you get.... BUBBLES!!!! That's where your bubble are coming from, fix the leak, refill the coolant, the bubbles should go away.
 

91stranger

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That's the game plan. I know the picture wasn't the greatest and that was why I put the arrow there that way you knew it was coolant and not just dirt or rust lol. Quite frankly, I'm sick and tired of fixing something on this truck every other week and it may get a for sale sign put in the dash if it doesn't stop being a b$#%h. I'd really like to find someone wanting to trade a full size 4wd for a 2wd ranger and then I'd be happy. This truck has made me loose a lot of hope in rangers.... They used to be low maintenance, good gas mileage trucks but this one has not been the case at all. I think it's partly due to the fact I got it at 99k and that's when shit starts going bad.
 

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That's the game plan. I know the picture wasn't the greatest and that was why I put the arrow there that way you knew it was coolant and not just dirt or rust lol. Quite frankly, I'm sick and tired of fixing something on this truck every other week and it may get a for sale sign put in the dash if it doesn't stop being a b$#%h. I'd really like to find someone wanting to trade a full size 4wd for a 2wd ranger and then I'd be happy. This truck has made me loose a lot of hope in rangers.... They used to be low maintenance, good gas mileage trucks but this one has not been the case at all. I think it's partly due to the fact I got it at 99k and that's when shit starts going bad.
You have one with the most problematic engine they ever put in the Ranger.
 

91stranger

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Yeah I realize that after working on it every week. It's great when it runs but it does not like staying running. I'm not hard on it either. Basic daily driver and hauling wood but it's 2wd so I don't go off the road much and I sure as hell don't drag race it. I wish it were a 5 speed...…. and 4wd...…. and bigger...… and not rusted out...….. and not breaking every damn time I touch it.
 


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