Jeep Patriot Forums banner

DIY: 2009 Patriot Tstats and Heater Hoses Reversed Mod

23K views 6 replies 3 participants last post by  cn90 
#1 ·
DIY: 2009 Patriot Tstats and Heater Hoses Reversed Mod

- This is a friend’s car 2009 Jeep Patriot with 60K miles. I am posting the instructions in case you guys need it, but I am rarely in this forum as I don’t own the Jeep, so if you have questions, post questions in forum.

- Symptoms: cabin heat appears for 5 seconds, then no heat! Possible culprits:

1. Bad thermostats. Not sure but at 60K miles, we decided to replace them anyway.

2. Car came with no Cabin Air Filter, checked the blower area, seemed clean with no leaves/debris (which in severe cases can block the heater core ---> no heat!). Anyway, I dropped the glovebox door (squeeze both tabs behind the glovebox door and dropped it down), install new cabin Air Filter ($15 at Autozone) just to prevent leaves from blocking heater core.

3. Heater Hose: INLET is hot, but OUTLET is lukewarm. Flushed with water: the flow was nice in both directions, so heater core is not clogged. Maybe “air lock” is the culprit: see the mod at the end (reversing the coolant flow).

- BTW, see the threads by todde702, he posted some very good info on thermostats:
http://www.jeeppatriot.com/forum/showthread.php?t=86613


PARTS:

- Primary Tstat 170F and Secondary Tstat 203F: “Motorad” brand are from autohausaz.com; about $45 for both.



- Factory is some kind of pink coolant (search forum), it is a debate here re coolant type (a debate I don’t want to get involved with). I have had good luck with Green Prestone, so we flushed the pinky stuff out and replaced with Green Prestone. Once you flush the engine block with water, there is always some water remaining inside. So 1 gallon (concentrated Prestone, not the 50-50 type) is good enough as system capacity is a bit less than 8L. Basically after a complete flush with water, fill with 1 gallon of concentrated coolant, then add distilled water. This way the system has 50-50 mix.

PROCEDURE:

1- Drain coolant is what the book says, but I didn’t want to get underneath with brittle plastic petcock, splashguard etc., so we simply flushed with water from above.

2- D/C the Plastic Air Intake (in front of the Air Filter Housing): twist the 2 knobs, remove it and set aside far from the car so you don’t step on it accidentally!

3- D/C the Rubber Intake from the Air Filter Housing: flat screw driver. Remember to re-attach the smaller hose to Air Filter Housing later. Lift the Air Filter Housing straight UPWARD, it is held by 2 rubber grommets.

4- D/C the electrical connector to the Temp Sensor at the Intake Rubber Hose.

5- Time to review some anatomy:
* Tstat Housing is held by three (3) 10-mm bolts:





View from engine side:








* The Primary Tstat housing is held by two (2) 10-mm bolts. The bottom bolt is a difficult one: use a 10-mm socket and extension: find the right angle to make sure you have a good bite! Do NOT strip the bolt!

* Note: the tstat gasket has a NOTCH that must fit in the housing’s NOTCH to ensure the air-bleed hole is at the top.

 

Attachments

See less See more
10
#2 ·
Part II

6- The issue of coolant flow: HOT Coolant ---> Big RED Arrow ---> Heater Core INLET (lower hose). COOL Coolant returns via the Heater Core OUTLET (upper hose). This is factory design with hoses criss-crossing. I suspect air is trapped on the OUTLET side and since that hose (BLUE label) goes downhill, it is difficult to get rid of “air lock” if air is ever introduced into the system.




7- So I did the mod by reversing the coolant flow. If you decide to do this mod, NOTE:

* Technically speaking you can D/C the heater hoses at the firewall, but the space is tight and you risk breaking that plastic connections, a big no-no!

* So I disconnected the Heater hoses at the Tstat Housing. Once the clamps are off, slide a flat screwdriver underneath the hose to break that bond between the house and the nipple. Then slide the hose out.

* Use a garden hose the flush both directions. You don’t want a water-tight connection here (you risk blowing up the heater core b/c municipal water pressure is 60-120 psi!!!). Simply flush the heater core with some water. In our case, no gunk came out, so heater core is good.

* To flush engine: garden hose in the big rad hose that we disconnected, just let it run for 2-3 minutes.

* To flush reservoir: d/c the small hose near the rad cap and point it down, then garden hose into reservoir.

8- Note that I reversed the Heater Hoses at the Tstat Housing. After this mod is done, I had decent heat, about 110F out of the center vent. So my theory is somehow air is trapped in the OUTLET, by reversing the connections at the Tstat Housing, during the engine cool-down period after a hot run, any trapped air flows through a more “natural” path Upper Firewall Hose ---> top of the Tstat housing ---> Upper Rad Hose ---> Reservoir.




PS: The factory tstat is 658-170, which is 170F, OK but this does not give the best heat for the people who live in the North.

So, if anyone finds the 658-180 tstat, please post, I am interested in that.

I did the tsat mod on my 2007 Honda Odyssey van (from factory 170F to Motorad 180F) and the cabin has nice heat, below is the thread on this 180F mod:
http://www.odyclub.com/forums/52-20...stat-changed-82-deg-c-motorad-thermostat.html
 

Attachments

#3 ·
NOTE re filling coolant:
- Open the rad cap (maybe tight), add coolant until it reaches the top. Air bubbles will slowly come up.
- Squeeze the rad hose a few times until all bubbles come out.
- Add coolant to reservoir.
- Close the rad cap, then run engine until hot, bubbles will continue to be vented into the reservoir. I understand the FSM says leave the cap open during bleeding (engine running) but I don't like doing it this way.
 
#4 ·
Tstat Alternatives: 180F vs 195F

For those who want hotter tstats, I'd recommend Motorad brand, which is the OEM supplier for Jeep tstats from factory. I have used Motorad for years w/o issues.

OReilly Auto Parts sells Motorad tstats.

- The tstat is the 54-mm type. It took me a while browsing through shelf by shelf to find these perfect fit.

* 180F tstat is Murray 4218 ~ $10.

* 195F tstat is Murray 15119 ~ $10.

- If you use this thermostat, don't use the O-ring that comes with it.
Instead use Mopar O-ring (or re-use the factory O-ring) but note:

1. The factory O-ring has a tiny bump on the inside groove that matches with the notch on the metal flange. Use a utility knife and gently remove the rubber notch b/c the alternative tstat has no notch.

2. The bleed hole location: mark it with Sharpie for easy install so the bleed hole faces 12 o'clock position.





 

Attachments

#6 ·
Very interesting that you found compatible 180 and 195 deg. T-Stats! That's awesome work. I'm curious if they see better fuel economy with a little more heat in the engine.
 
#7 ·
My 2007 Honda Odyssey van came from factory with 77C tstat. Swapped to 82C tstat back in 2007, for the last 6 years, the Honda Odyssey cabin heat is fantastic, gas mileage goes up 1-2 mpg.

For the 2009 Jeep Patriot, after the swap to 195F tstat (90C), the cabin heat improved a tiny bit, so I knew the poor cabin heat is caused by clogged heater core.

Installed the Heater Core by slicing the pipes (1-2h job, instead of the 8-10h job with dash removal). So far so good, nice heat in cabin.

Below is the DIY: 2009 Jeep Patriot Heater Core:
http://www.jeeppatriot.com/forum/showthread.php?t=177729
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top