over the weekend i picked up a 2006 with 83k miles on it and has smod.

pulled the pan, the screen, cleaned everything out and bypassed.
added new fluid and its driving now.

going to do a couple more drain and fills until the fluid is happy and see if i cant save it.
if so itll be the 4th smod vehicle ive gotten that ive been able to save by changing the fluid.

 

Lucky you! Mine got to the TCM but after replacing that and a good flushing, mine has been good during the subsequent 4 years.

 

WARNING, This issue can occur in newer trucks! I just had the trans in my 2016 Frontier rebuilt due to coolant contamination at 104K miles. I would advise all to bypass the internal radiator cooler. It costs nothing and will prevent a very expensive repair.

 

Can you get us the #s off of the old radiator? This would be a big help..

 

I know this is an older thread and I did skim through some of the posts but just don't want to read all 64 pages to find an answer. I have a 2005 Frontier with the 2.5 4 banger engine. I had an experience yesterday I can't explain. My wife and I had decided to take a short trip up to the Smokies today which is about 125 miles from here. We drove down to a small town to have lunch which is about a 48 mile drive round trip.

I checked my radiator and tires to make sure all was good for the trip to the Smokies. I noticed I could not see the water in the radiator so I topped it off with straight antifreeze and filled the reservoir as well but I overfilled the reservoir.

We drove the 24 miles down to the small town with no problems. We let the truck idle while we ate. When we started home the truck started jerking badly like the transmission was real low on fluid. I pulled into a service station and noticed the truck was running very hot so I shut the engine off. That is when I saw a long streak of antifreeze where we had lost the fluid.

We sat there for a long time to allow it to cool off. I bought two gallons of water to see if we could make it back home. The strange part is the radiator wasn't spewing extremely hot water out of the fill cap. There was no puddle of water under the truck. There is no leaks in the hoses or radiator. The radiator did hold a gallon and maybe another cup water last night.

I just went out and checked and the radiator is full, and the water is clear, I haven't put antifreeze back in it yet. The reservoir has very little water in it as I didn't put much in last night. I can not figure out why it ran hot going down there and not on the way back. Could it be I didn't do the burp thing when I topped it off with antifreeze before the trip down?

The truck did not overheat at all on the 24 mile drive back home. Does anyone have any suggestions?

 

First check:
Cap w/ spring goes on reservoir while simple/straight cap goes on rad. Perhaps you mixed them up?

Best to only deal w/ the reservoir when checking/adding fluid. Add, then drive and check whether more needs to be added. Leave rad alone.

 

After doing more checking, you are dead right, I got the caps mixed up some way. I feel so stupid lol

Thanks to all of you who pitched in to help me, I appreciate it very much. And thank you Shift, I really do appreciate your help.

 

Caps as @shift_RUSH said.

Also, if you add too much, the truck will burp the coolant out of the little plastic nipple on the top of the reservoir. it runs down all over the vender liner so it looks horrible and can be alarming the first time.

With the engine cold, look at the level on the reservoir, then start the engine. if the reservoir gets sucked dry, you need to add a few ounces. Do this over the course of a few days and the level will stabilize.

 

Just to ease your mind the 4 banger never suffered from SMOD, that was 6cyl only.

 

That's good to know, I did not realize this.. the tranny jerking is alarming though. He did not mention checking tranny fluid unless I missed it.

 

once the truck cooled off and I added the fluid again, the transmission shifted perfectly again. I figured there must be a sensor that would shut the engine down when severely overheating.

On getting the radiator cap and reservoir cap mixed up. I thought I was sure the one that has the seal at the top and another seal spring loaded was the radiator cap and the flat cap was the reservoir cap.

 

@shift_RUSH is the fellow who set me straight, I can't thank him enough. I do for sure agree, this is a great forum to get the right information needed.

 

That happened to my frontier. It turns out it is a known problem and (in my opinion) should have been the subject of a recall.

 

So the Cross Contamination is only an issue on '05-'10 Frontiers?

 

For the most part, yes, there will always be outliers as anything built by man is subject to failure at any time, but the updated radiators have a vanishingly small percentage of failures noted.

 

Great. Mine is a 2019 so hopefully I'm all good to go.

 

The 2.5/4-cyl Frontiers w/ auto trans never had this radiator cross contamination issue. Worth re-mentioning though, nearly all auto trans equipped vehicles use this type of system both to warm up the trans fluid as well as cool it down. Therefore, the opportunity for cross contamination is present, fwiw.