Radiators, Antifreeze & Strawberry Milkshake Of Death (SMOD)

Just a Hunter

Bought an X
I'm not sure if this posting is best served in "general maintenance" or in "drivetrain"
Regardless, it's of enough importance that I wished to share it with our community.

The Nissan Xterrra is a rather reliable vehicle but, there is one HUGE issue to become aware of, which is SMOD.

Basically, from 2005 until apx 2009 there were known issues with the radiators of Nissan Xterras with automatic transmissions. Generally speaking, there are transmission lines which run through our radiator. A flaw in the production of the Calsonic radiators which Nissan used in our vehicles could allow antifreeze and ATF to mix and enter into our transmission. Ultimately, this would destroy our transmission.

The term SMOD comes from the appearance of the fluid in your overflow tank, radiator and transmission fluid. Basically, SMOD will present as a nice frothy strawberry milkshake.

Typically, an Xterra owner will first notice SMOD by general transmission problems which may include hard shifting, slipping, failure to shift or a rumbling sensation while driving.

What can you do to prevent SMOD?
Check the Nissan part number on top of your radiator to confirm if its known to be affected with SMOD.

21410-EA200 (early 2005’s.) Associated with SMOD

21410-EA205 (2005 – 2009). Associated with SMOD

21460-EA215 (2005 - 2009) Associated with SMOD

21460-EA265 Associated with SMOD

21460-ZL11A (2009-2010) isolated reports of SMOD found on the net

21460-ZL31A no cases of SMOD found by searching the net

21460-9CAOE (2011 – 2015 ) No known cases reported on SMOD.

If you have a 2005-2010 Xterra, check your vehicle for any signs of SMOD.
With a cold engine and no pressure on your hoses, check your overflow tank, radiator and transmission fluid for any signs of contamination.

If signs of smod are found, stop driving your Xterra until you can address this problem immediately.
In this case your best hope is to replace your radiator followed by a full flush of your radiator fluid. Note that a drain and fill of your pan only replaces a few quarts of fluid and you need to replace all your atf or risk recontaminating the new fluid your installing. The net can provide instructions on how to flush our transmission fluid.

If you dont notice signs of SMOD and yet your part number reflects a radiator associated with SMOD , you have two options.

You can swap your radiator (best option)
Or you can re-route the lines entering your radiator to prevent atf fluid from circulating through the radiator. There are mixed opinions on this matter and I would suggest this option as a preventive measure until a new radiator can be installed. Obviously, doing a by-pass of the radiator can effect the cooling of the fluid in your transmission. This can be an increased issue for those which tow or live in hotter regions of our country.

(Disclaimer: Note, all the information shared on this post should be considered as "entertainment" and needs to be referenced and confirmed on your own. Please become educated in regards to what has been shared and contact a certified mechanic prior to making any changes to your own vehicle.)

To be clear, I should be considered a highly trained unproffessional
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Just a Hunter

Bought an X
Information from the net.

"In October 2010, Nissan extended their radiator assembly warranty from 3 years / 36,000 miles to 8 years / 80,000 miles after reports from a “small percentage” of owners with internal cracks on the oil cooler tube" (Nissanproblems).

There were cases in which some Nissan owners found dealing with their dealership to be somewhat complicated. To be clear, there seemed to be confusion if the extended radiator warranty covered the damage to their transmission.

Some owners were of the opinion the extended warranty was used as a means to evade a recall.

Approximately two years after the warranty extension, Nissan was involved in a class action suit.
Following this event, Nissan is said to have changed their warranty once again ( Nissanproblems).

  • Up to 8 years/80,000 miles, whichever comes first, extended warranty coverage applies with no customer co-pay.
  • After 8 years/80,000 miles, whichever comes first, up to 9 years/90,000 miles, whichever comes first, extended warranty coverage applies with customer co-pay in the amount of $2,500.
  • After 9 years/90,000 miles, whichever comes first, up to 10 years/100,000 miles, whichever comes first, extended warranty coverage applies with customer co-pay in the amount of $3,000.
Sadly, I have read the deadline to file a claim has run out.

It appears the North Carolina Consumer Council petitioned the NHTSA to investigate this known issue.
Nevertheless, it's been told the NHTSA closed this case after no safety risk was identified. (Nissanproblems)

Catastrophic transmission failures are still taking place.

What can you do? Become familiar with the information which has previously been shared. Prepare to perform a radiator bypass or swap your radiator asap. Do not take for granted your one of the lucky ones which will not experience this problem.

Link: http://www.nissanproblems.com/coolant-leaks-destroy-transmission/
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Just a Hunter

Bought an X
When shopping for a radiator, there are plenty of choices to consider .

I've started a list of some of the radiators which I would purchase.
These radiators are listed by retail sites and not by any particular preference.
As always, check the model number to confirm the item you choose fits your application :)

Koyo (Koyorad) A2807 for 2005-2015 Xterras.
Cost would be apx $155 after an online 20% discount

CSF 3196
Cost $84.79 Rockauto.com

Spectra Premium CU2807
Cost $108.79

Denso Radiator 221-3409
Cost $109.99

Mishimoto R2807-AT
Cost $178.95

Please add to this list if you have been pleased with a radiator which has not been listed.

Just a Hunter

Bought an X
Basic steps to follow when replacing your radiator.

Step 1
Position a container under the radiator drain to catch the coolant.

Step 2
Drain the coolant from the radiator by removing the drain plug located on the bottom of the radiator

Step 3
Remove the upper and lower radiator hoses. This can be performed with a pair of angled needle nose pliers. However a set of hose clamp pliers make this alot easier.

Step 4
Remove the intake air duct from the engine. This is necessary for clearance to allow access to the radiator shroud.

Step 5
Remove the lower radiator shroud. This item is attached to the main shroud using two snap-in tabs on either side of the lower shroud. Some may find it easiest to release these tabs with a screwdriver. Next remove the shroud from the engine compartment.

Step 6
Locate and remove the two bolts which secure the shroud to the radiator. Slide the radiator shroud out of the engine compartment and set it aside.

Step 7
Remove the overflow hose from the nipple at the radiator fill neck. Additionally, you can remove the transmission cooler lines from the radiator.

Step 8
Remove the two radiator mounting nuts from the upper radiator support, and lift the radiator straight up and out of the engine compartment. Swap the mounting brackets from the top of the radiator to the new radiator before installing it.

Step 9
Insert the new radiator into the engine compartment and engage the pins on the bottom of it with the holes in the lower radiator support. Install the nuts on the upper radiator mounts.

Step 10
Install the transmission cooler lines ( I recommend new transmission lines) and overflow hose. Return the shroud into the engine compartment and align the mounting tabs on the bottom with the slots in the radiator support. Install the two upper mounting bolts

Step 11
Install the lower shroud. It will just snap into place on the main shroud. Install the upper and lower radiator hoses (I recommend new hoses) and attach the hose clamps.

Step 12
Fill the radiator with new coolant and test run the engine. You will need to keep adding coolant until all the air is out of the system and the thermostat is fully opened. During this process, carefully squeeze your upper radiator hose to assist in " burping" your radiator. When it will not accept any more coolant, and no further bubbles are noticed, install the radiator cap and verify that you don't have any leaks.

Step 13
Lastly, fill your overflow tank to the recommended level.

Just a Hunter

Bought an X
Recently, it was brought to my attention how confusing the antifreeze product choices have become.

In addition, many auto manufacturers will add to this issue by stating " The use of our product is recommended ", but they dont necessarily state what to look for outside of their product.

With this in mind, I hope to wade through some of this confusion.

For starters, there are several similarities between the different types of antifreeze.
As an example, Modern antifreeze is typically 96-percent ethylene glycol, which provides the freeze protection, and four-percent additives.

In most cases, a 50/50 blend of a modern antifreeze will protect your freeze point to -34 deg.

Additionally, a well maintained antifreeze will provide a certain level of corrosion resistance, however this can diminish over time. Generally, half of your antifreeze additives are used to protect against acid buildup and the other half limit corrosion.

For years, a "conventional" inorganic green antifreeze was the standard product used by most manufacturers.

Around 1996 GM developed a "organic acid technology," or OAT antifreeze which is orange in color. This product was implemented in 1996 models in the U.S. and used the name Dex-Cool.

The benefit of an OAT product is long-life corrosion protection, which can last up to six years or 100,000 miles . Obviously, this is a benefit over the two years/50,000 miles that was typical with the old green stuff.

Nevertheless this product can destroy old-style radiators with lead solder, and the inhibitors work too slowly to protect against the sort of corrosion that happens so fast it actually erodes metal-for example, the cavitation likely in the imperfectly designed water pumps of older cars.

With this being said, it should be clear that you should never use a hoat based product in a system designed for a conventional product.

As time passed, the Asian market designed their own antifreeze which is based on OAT technology with a few changes.

This product is a long service life product based on a proprietary Phosphated Hybrid Organic Acid Technology (P-HOAT). This ethylene glycol based product contains a mixture of organic additives and phosphate and DOES NOT contain any silicates, borates, nitrites and amines.

P-HOAT happens to be what we need to use in our Nissans as well as vehicles made by Toyota, Nissan, Honda, Hyundai, KIA & most other Asian vehicles.

This product is typically either Blue or Pink in color.

Disclaimer: As always, I am to be considered a highly trained unproffessional and the information shared should be considered my opinion until proven factual by yourself.
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Just a Hunter

Bought an X
The morning "Gurgle"

A common issue with our Xterras is a weird noise which may be heard in the morning for the first few minutes of driving. Basically you will hear a sloshing noise which will come from the dash region .

This noise is common enough that it's been provided it's own name, the morning gurgle.

Basically, you have air trapped in your cooling system and or heater core.

Here is a tip which has worked for me

Park your truck in an position which elevates the front of your truck.
Mechanic ramps work best, but a couple patio stones will be fine.

Go inside, eat a meal, watch some tv, take a nap and return once your cooling system no longer has any pressure in it.

Remove the caps from your radiator and overflow tank.
Make sure your overflow cap is the one with the spring, it's easy to get these swapped.

Fill your radiator, crank your engine and once the coolant starts circulating throuh the engine give your radiator hose a squeeze.

You should see some bubbles appear.
Repeat the process of keeping your radiator filled and delivering a squeeze of the radiator hose until you no longer get any bubbles.

Check your radiator is filled properly and install the radiator cap.
Fill the overflow tank and install its cap .

Check the fluid level on your overflow tank after you have driven your X.

Be pleased with having removed your morning gurgle.

Just a Hunter

Bought an X
When stopped and idling with your heater on. are you experiencing cold air being blown through your vents.

If so, check your radiator overflow tank the next time your engine is cool and your coolant system is without pressure.

Fix: Fill your overflow tank to the proper level . A simple fix for sure that often remedies the idle cold air scenario
Reminder: squeeze the upper radiator hose to confirm your coolant system is without pressure before uncapping your overflow tank