Hello sirs and ladies of the forum!
My issue is as follows. I bought a 2006 Voyager 2.4L Diesel 141Hp this summer. I noticed that the temp needle wouldn't rise half way but somwhere between middle and quarter, but beeing summer i didn't give it much importance.
Winter came, and my engine started running verry cold so i went to a mechanic to replace the thermostat. I have found out that the original code thermostat is super duper expensive for my buget, and the aftermarket ones don't have a socket for the heat sensor (NONE OF THEM). I googled and searched youtube untill i found Andy Brown's fix for the issue, and a link in the description that has sent me to this forum. My car runs great now, the engine heats properly, the only issue is when i drive it faster or go uphill for a few minutes, the temp needle spikes up very quickly, and it falls back down if i slow down or start going downhill.
In this video Andy speaks about drilling a hole in the 2'nd thermostat body, thing i am quite positive the mechanic i visited didn't do.

Can the tiny hole be the issue? or ... is there any other place where i can fit the heat sensor? Thanks in advance for all your answers and fixes, i realy can't afford paying half a sallary on a freakin' thermostat *(I know, living in eastern-europe sux)

Link to Andy's video

 

To be honest it sounds like your temperature sensor is working (you mention the needle changing). To me this more sounds like you don't have the correct coolant level and therefore depending on your incline, means flow isn't moving correctly, meaning you have air moving over the current sensor given an incorrect reading.

Check your coolant level and post up the results, much cheaper fix and a lot less risk then drilling the hole.

I had a 2.5 diesel prior to my petrol and had the same issue and did the same thermostat fix, I didn't drill any hole and didn't experience the issue that you are currently experiencing.

 

The coolant level is normal, anitfreeze + water tested at -38oC

 

What is heat flow like from the front air vents? It should be very very hot when the needle is around halfway, also it should stay at that temperature and not drop down, you may have a blocked heater matrix that could be moving some "crud" around the cooling system.

A good backflush may help out with the issue as well, make sure to do both the radiator and the heater matrix.

 

It used to be just a little warm thanx to the auxiliary heater before i did the Andy mod, now it is as it should be, you can drive in t-shirt and shorts in mid winter.
The heat sensor is still in place fitted onto the old thermostat, i didn't change it bcz the relatively reasonable priced ones don't have a place to fit it onto.
I have pictures:
The aftermarket cheap one



the "original one"





as you can see they look the same, they fit perfectly in place but the cheap version doesn't have a fitting for the temperature sensor.
I hope you can all understand my problem , i am a musician not a mechanic

 

Do the job the correct way. (1) Foreward flush [notnbackflush] to get a lifetimes gunk out (2) use only HOAT Comma G05 Xstream coolant.

When I did my "inlineMOD" I :

- used 5L G05 +5L de-ionised water
- hose pipe in the expansion bottle, loosen bottom hose
- clean hose in @ same rate as dirty out
- when perfectly clear
- tighten bottom hose
- 5L G05 + 5L de-ionised in expansion bottle
- start engine / full heat / full fan blower
- let it ''burp' untill it reaches temp
My MOD with pics is on this forum, best of luck.

 

I asked the mechanic to do a full cleanup of the cooling instalation, what he had done, i wouldn't know... My initial question was regarding the drilling of the holes in the "mod thermostat" might it fix the temp spikes at high revs?

 

"might it fix the temp spikes" , I doubt it its only to allow air out not water in it will let water pass but its minuscule.

I did drill holes in the Renault 5 stat used in my MOD because it didn't have a jiggle valve.

see + here and see here for air dam.

You will never get an answer till you front-flush and clear the whole system including the matrix properly my friend and when you have .. .. .. use proper HOAT 05. Best of luck.

 

Just doing a little Voyager thingy through Shpoch the other day and what comes up but someone selling the proper thermostat that bolts on back of cylinder head. £20 or £30 they wanted for it, amazing what you can find..
Oh and another thing that questioned my knowledge of flushing out engines and radiators. "Or many be I'm just getting old and judgement not right". Was an answer to someone who's engine was overheating. The answer was to flush the engine and radiator out with a low pressure trickling hose as it clears the crud out properly. Well was going to suggest a blasting hose but, had to think here, emmm, I passed it over...

 

Good find on the stat.

The answer on why front and never back-flush :::

https://www.chryslerforum.com/forum/chrysler-voyager-town-country-21/overheating-23086/#post83702