Changed Thermostat, Nightmare!

[Fatboy 18]

Anyone got a spare coolant temperature sensor? Need one fast.
part number 4848110

Been doing a bit of work!
changed the thermostat, went to undo the 3 bolts holding the thermostat housing and this happened!

Note: busted bolt! Not Good
Head of the bold just twisted clean off! WTF!
Took me almost two days to get the broken part of the bolt out.
Tried putting a set of grips on it, that didn't work
Filed top of bolt flat then using centre punch made a hole it the top of the bolt, used various size drills to drill down centre of bolt and slowly increase diameter to get out to the bolt threads,
Taped into the bolt using hardened reverse thread easy outs. Guess what happened next? Yep they snapped off down inside the bolt hole! Arrrrrrrrgh
More new drills needed to remove the so called easy outs! Finally after removing the bloody easy out I used a dremel tool with a small diamond grinding bit to slowly get out to the bolt threads. I managed to remove about 3 of the threads but the rest were not going to come out so had to retap the hole.
I did not have the correct tap tool so made my own. I used a old bolt with the same size threads and cut a vertical slot in the threads which would act as a cutting tool, using lots of lube and pressing down onto the bolt rotating it back and forwards I cut an thread down the hole.
What a PIA. But all done without needing a helicoil and the block saved.

All cleaned up, new 180 thermostat


Used a small amount of holarmar blue gasket jointing compound, (you don't have to but I don't trust gaskets by themselves).






Now need a temp sensor.

One thing I will say about doing this job is a WARNING When undoing the fuel quick release prior to removing the inlet manifold. I had pulled the fuse relay in the trunk of the car, released pressure from the brass schrader valve then disconnected the fuel quick release, There was a lot of fuel in the manifold and I was not expecting that much! If you ever tackle this job I would recommend pushing the car outside of the garage and make sure you have a fire extinguisher to hand (just in case) There were a lot of fumes! better not smoke either!

[Geronimo]

Just a quick question since I am going to be doing this soon. Is there a tool needed for the quick release on the fuel line? Is where the fuel line threads into the intake not a flared fitting? Just wondering why the pressure can't be release and then the fuel line unthreaded at the top of the intake. I can hardly get my hand down there where the quick release is.

[Fatboy 18]

Once you remove the window cowl, the gap is a bit bigger. You can also move the intake manifold forward to allow you to undo the quick release, no special tools needed I did it with one hand.
What was an absolute bitch was undoing the two electrical connectors to the coil packs. I managed to undo the connectors with the plug leads in place but you are working blind! I might have said one or two swear words!

After disconnecting the fuel line i did use a couple of bungs to cover the main fuel pipe and manifold fuel pipe, its a little unnerving having your hand covered in petrol and fuel leaking everywhere! BE CAREFUL.

Torque sequence for the inlet manifold is also very important, start from the middle and work your way out either side 7/16 1/4 drive socket Torque to 11 Newton meters

[C.J]

Dang Mark, removing that busted bolt was rough! Congrats on getting it done. Do you know if the bolt that sheared off was the correct grade factory bolt?

Thanks for the warning regarding the amount of fuel in the manifold. Had you run the engine after removing the fuel pump relay?

[Fatboy 18]

Dang Mark, removing that busted bolt was rough! Congrats on getting it done. Do you know if the bolt that sheared off was the correct grade factory bolt?

Thanks for the warning regarding the amount of fuel in the manifold. Had you run the engine after removing the fuel pump relay?

No I didn't think of that! I had already drained the coolant the previous day.

The bolt was the stock factory ones 7/16 with the torx head in the centre. at some point moisture had got into the holes and caused
"Galvanic Corrosion", this is where metals of two different types weld themselves together! I left the bolt in soak with penetrating oil overnight and that did not work, I also used Heat with a small gas blow lamp but the wiring harness is right next to the hole and even using a soldering matt heat shield things started getting hot! so gave up with that.
Here's a picture of the couple of bolts I used to tap the new thread, bear in mind that "was" a straight Vertical cut in the bolt, so you can see the strain on the bolts cutting a new thread!

[Geronimo]

Is this a common problem with these or just a bad happening?

[Fatboy 18]

Is this a common problem with these or just a bad happening?

I honestly have no idea? My inlet manifold was only just being held on! I got the car in 2008 and have never had the manifold off before, two bolts were missing! and the rest ALL loose! I never had cause to check them before? As for the actual thermostat cover all three bolts showed signs of corrosion!
11 newton meters is not that tight, Yet the bolt was going nowhere.

Best of luck

[GTS Warp]

Thanks for the tips Mark! I'm getting ready to do this myself. Just been putting it off because I know it's a huge PITA!

[Fatboy 18]

Some of the wreckage from that bolt!


Add at least another 4 broken drill bits to that lot!

[Geronimo]

When you said fuel spilled out everywhere is there any way to catch it from going everywhere?

[GTS Dean]

If anyone else is going to tackle this, I would suggest that after removing the intake manifold, you grab a small drift punch that fits down inside the Torx socket, or a center punch, and a 2lb. hammer. Carefully square up over each bolt and give each one 2 or 3 good sharp strikes. This will transfer shock down through the bolt, into the thread area, and hopefully free up the threads so the bolt will turn. It could require a couple of tap/wrench turn/tap cycles if a bolt is being stubborn.

[Fatboy 18]

When you said fuel spilled out everywhere is there any way to catch it from going everywhere?

Nope. Best thing to do is what CJ suggested,
1/ do not drain coolant
2/ remove fuel pump relay in trunk.
3/ run engine until fuel runs out.
4/wait for engine to cool down then remove inlet manifold.
5/Then drain coolant
6/attempt to undo 3 thermostat housing bolts......if they come out, celebrate with Beer
If not, post problems here!

[thetalonguy]

I thought it was possible to remove the Tstat without fully removing the IM / Fuel? I could have sworn I read somewhere that you could just loosen the IM and you could get to the Tstat to swap out? LOL, well I was kind of hoping that was the case since I'll be doing that shortly.

[Geronimo]

Nope. Best thing to do is what CJ suggested,
1/ do not drain coolant
2/ remove fuel pump relay in trunk.
3/ run engine until fuel runs out.
4/wait for engine to cool down then remove inlet manifold.
5/Then drain coolant
6/attempt to undo 3 thermostat housing bolts......if they come out, celebrate with Beer
If not, post problems here!

I have never had to drain coolant to change a T-stat.Release pressure from cap on fill tank, then I disconnect the upper rad hose and prop it up. Then just remove the t-stat housing and keep a shop vac handy to evacuate any overflow from the opening. That is on small block chevys tho. This will be my first viper.

[AZTVR]

I thought it was possible to remove the Tstat without fully removing the IM / Fuel? I could have sworn I read somewhere that you could just loosen the IM and you could get to the Tstat to swap out? LOL, well I was kind of hoping that was the case since I'll be doing that shortly.

Yes, I did not disconnect the fuel line on my 2002 when I changed out the Tstat. Just lifted the intake manifold high enough to put some short pieces of 2x4 in there to hold it out of the way.

[thetalonguy]

Yes, I did not disconnect the fuel line on my 2002 when I changed out the Tstat. Just lifted the intake manifold high enough to put some short pieces of 2x4 in there to hold it out of the way.

Ahh, thank you Sir for confirming :-)

[Fatboy 18]

Yes you can do that, but I wanted to clean out all the crud under the intake manifold and also wanted to clean the underside of the manifold too.

My coolant required changing as it was over 3 yrs old. That's why I drained it.

[Geronimo]

Yes you can do that, but I wanted to clean out all the crud under the intake manifold and also wanted to clean the underside of the manifold too.

My coolant required changing as it was over 3 yrs old. That's why I drained it.

Gotcha. I run the Evan's coolant so it never has to be replaced again. Glad I don't have to dump it.

[Fatboy 18]

NEXT TIP..........

Now bear in mind that the top rad hose may not have ever been disturbed since leaving the Factory (in my case 16 years).
Thermostat changed and hose reconnected

So Today, got onto the freeway and then came to a halt due to a serious accident a couple of miles up the road. Traffic gridlocked and after an hour of sitting in stop start traffic, My top radiator hose blew out sending new coolant all over the engine that I had spent days cleaning.

So the RECOMMENDATION is to FIT A NEW HOSE.

Had to wait for the recovery service for an hour, meanwhile cars passing at nearly 70 mph!......NOT GOOD!


The Highways Agency towed me into a service area where I then waited for the recovery truck to turn up....
What a truck, Brilliant.


The busted hose, it burst right where it joined onto the thermostat housing!


Be Warned!

[DaveW]

Hey, Mark. Sorry for the bit of trouble with the radiator hose (nice ride home, though!). I had the rad hoses replaced by Tom Sessions a few years ago with SnakeOyl products. Love 'em! If I recall, you have an '00? Last week Tom replaced the heater hoses which were soft and "bulging" in places on my '00 (45K miles), along with everything else rubber on the engine.

My GTS is an Oct 2000 late production car and has a combination of early and late GenII heater hoses (not year specific) offered by SnakeOyl. Highly suggest sending photos of each hose for comparison before ordering and r&r. Several of our Carolinas' members with '00 models have experienced similar fitment problems. Thanks to Tom for making it all work!

The 180 thermostat is amazing! Tom also replaced the original spark plug wires with Adam Brennan "Quality" wires, and after 16 years with the original wires, the HP increase is significant!

Stay safe!

[SteveMat]

I am pretty much in the middle of doing the same thing but have to replace the timing chain cover gasket. Taking the different pieces of advice on the threads, gave the thermostat bolts a whack with a punch pin and they came right out. After seeing the "fun" you were having, I was willing to try anything. They are corroded compared to the intake manifold bolts, assuming you got new bolts, where did you get them from?

And yes, there is a lot of fuel in the intake manifold, I thought the whole fuel tank was empting out...

[Fatboy 18]

I am pretty much in the middle of doing the same thing but have to replace the timing chain cover gasket. Taking the different pieces of advice on the threads, gave the thermostat bolts a whack with a punch pin and they came right out. After seeing the "fun" you were having, I was willing to try anything. They are corroded compared to the intake manifold bolts, assuming you got new bolts, where did you get them from?

And yes, there is a lot of fuel in the intake manifold, I thought the whole fuel tank was emptying out...

Well it turns out that those 11mm bolts with the torx head are no longer available, they are replaced with a standard 11mm Hex bolt.
However I have some good OEM spares with the Torx head.
Drop me a PM with your address and I will send you 3 replacement ones

[98RedGTS]

Newest member in the snapped off bolt club. Is there a t-shirt or support group? Thanks to this thread I just started at drilling it out. 4 hour detour in my maintenance day.

[Fatboy 18]

Sorry to hear that, Just take it slow, is it the same bolt position as mine or one of the other holes?

What year is your car? My car was built Dec 1999 but is a 2000 model.

[98RedGTS]

Same exact bolt. Even sprayed with penetrating lube 4 hours before starting it and I also hit it in the center with a hammer. Other two came out smoothly. Car is a 98. Got it drilled out and new bolts installed.