Coolant reservoir full

[DaleInTN]

I have an '89 F-350 with a NA 7.3l. The last couple times I've checked the coolant level in the radiator I've had to add coolant. For the first time the other day I had a small puddle of coolant around the driver's side steer tire. I pulled off the overflow tube to the reservoir and when running (not at temp.) there is a small trickle of coolant flowing from the radiator to the reservoir. Is it possible that my radiator cap is bad, or is it something else?
Thanks for your help.

 

[My1500DollarTruck]

Well I just replaced my radiator and thermostat in my 7.3idi. I would suggest the following:

1) remove radiator cap
2) start engine let run, if you still have a working fast idle, the temp switch opens at 114F range to give you an idea where your temps are at when the fast idle goes to parked idle.
3) keep an eye on the stock gauge as a reference as well
4) feel the heater hoses, they have circulation all the time, are they getting warm:
5) feel the top radiator hose, no flow will go into it till the thermostat is opened and will be cool as compared to the heater hoses.
6) once top radiator hose starts getting hot (thermostat now open), watch the radiator coolant to see if its flowing
7) if all that appears as it should, put a new 13PSI lever radiator cap on it and test
8) if gauge is showing warmed up, but no hot flow from your upper radiator hose, your thermostat maybe stuck closed

Hope that helps,

 

[DaleInTN]

I have to say, the coolant was flowing before and after the high idle kicked off, so it wasn't cold.... just wasn't up to temp.

I have a new radiator, upper and lower hoses, and thermostat to put in. Should I just do that (since I have the stuff and was planning anyway) and see if that takes care of the problem?

 

[IDIBRONCO]

I'd replace the cap first if it was me. If you are wanting to replace the other parts anyway, it may be a good idea to make sure that there's not another issue first. I'd still lean toward a new cap at this point. Hopefully, you've been on here long enough to see that you should only use a Motorcraft thermostat.

 

[DaleInTN]

Copy that on the Motorcraft thermostat. I've seen a video on YouTube of a 6.9 that was leaking coolant really bad into the coolant reservoir. Mine is not bad at all, it's just a trickle that goes over to the reservoir. So I'm really hoping it is just a radiator cap. The radiator cap seems a little iffy in my opinion already anyways.

 

[IDIBRONCO]

That's a good sign that it's the right place to start. I always prefer to start with the easier, cheaper possible fixes first.

 

[Thewespaul]

This is why you always use motorcraft...

You must be registered for see images attach

 

[IDIBRONCO]

That's a big ***? right there!

 

[DaleInTN]

Yep only Motorcraft glow plugs and thermostats

 

[Hydro-idi]

This is why you always use motorcraft...

You must be registered for see images attach

I found the exact same thing when I replaced my tstat years ago in my old 87 pickup. Sometimes aftermarket parts are good, and sometimes they are pure $h!t.
Oem is the only way to go with this specific part.

 

[DaleInTN]

I put a new cap on and it didn't leak out to the reservoir. After further inspection, the cap said Motorcraft on it..... maybe the original cap???

 

[79jasper]

30 year old truck.... no point in trying to question it. Lol

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[Jason1377]

This is why you always use motorcraft...

You must be registered for see images attach

do we even want to know where that came off of or how long it was there, seems a big chunk of metal

 

[Thewespaul]

This came out of an idi, Napa brand thermostat causing some severe overheating

 

[IDIBRONCO]

Pretty easy to see why.