Halloween Thrills! -- Changing the thermostat on the Eurovan

     

Over the last few months, I've noticed that the EV was running a little hot.  It wasn't overheating but the engine temp would creep up.  The hottest it got was when my son and I went paddle-boarding back in September.  I had the van on while we used the electric air pump to inflate the boards.  By the time we had both boards inflated, the temperature gauge was reading at about the three quarter mark.

    I'm not new to overheating problems in cars.  I've gone through bad radiators, blown head gaskets, collapsing lower hoses, and even metal shavings in the cooling system, (thanks NA Miata).  It's important to deal with overheating issues early as a twenty dollar problem can become a two thousand dollar problem if you ignore it.  When chasing down an overheating problem, it's best to start with the small stuff and work up.  

Step 1:  Make sure you have enough coolant in the system.  Coolant can dissipate over time for various reasons.  In checking the EV, coolant wasn't my issue.   

Step 2:  Replace the thermostat.  I was at Step 2.  Thermostats are cheap and easy fixes.  They are also a major cause of overheating problems in vehicles.  No stats here but I would wager 50% of overheating issues with cars is from a faulty thermostat.  

I'm not new to replacing thermostats.  On a lot of cars, it's an easy task.  The thermostat housing sits on top of the engine, it's held by two bolts.  You drain the system of coolant, remove the two bolts, pop out the old thermostat, pop in the new one.  You may need to add a little RTV but otherwise, it's pop out, pop in and bolt back up.  With this kind of set up it's a fifteen to twenty minute job and easier than even changing the oil.  

The worst thermostat replacement I ever had to do was on my 2000 Saab 9-5.  The procedure is the same but the thermostat housing is located on the backside of the engine.  It required me to pull some extra parts, straddle myself across the engine and then remove, replace and re-bolt everything by feel.  After replacing my thermostat on the Saab, I was sore the next day.  I had essentially been tricked into doing auto mechanic yoga. 

My old and well loved, 2000 Saab 9-5.  

On Halloween this year, I figured I had some time to replace my thermostat.  We had plans to grab lunch and play mini-golf with my son and daughter.  I figured as they are teens who tend to sleep in late, I had about two hours to get it done.  I had watched videos and say it was probably a thirty minute job and I've learned that almost without fail, if a job is quoted as X time, if I double that amount, I am usually dead on.  My guesstimate is that it would take me an hour.  Plenty of time to get it done, test it out and grab a shower.  As Lee Corso is fond of saying, "Not so fast my friends."

It started out pretty simple and followed the Youtube videos I had seen.  I lifted the hood, opened the reservoir cap, removed the 13 mm drain bolt and let the coolant drain. 

13mm drain bolt.

 Finishing draining from the tube before I moved onto removal of the lower hose

  So far so good right?   Next, I moved over to the lower hose.  It requires me to loosen the clamp, pull the hose away, (move the catchpan to the other side to catch the coolant), let the coolant drain into the pan.  Once the coolant is drained, then I remove the two 10 mm bolts that hold the thermostat housing.  

Lower hose and clamp

Close up of lower hose and the two 10mm bolts that hold the thermostat housing.  

Again, no problems here.  Other than me laying on my back, this is going very well in relation to other times I've replaced a thermostat.  

I popped out the old thermostat and placed the new thermostat in.  It is a bit tight removing the housing bolts and tightening them back.  They are in somewhat awkward positions.  I was able to manage by swapping to a short extension on one bolt and a mid sized extension for the other bolt.  It took a bit of maneuvering but I was able to get everything back together and I was doing great on time and then....

Old thermostat.

And then, I made a couple of dumb mistakes and I ran into an issue.  

The two mistakes I made was that I didn't fully inspect the o-ring that came with the new thermostat and I didn't check to make sure it wasn't leaking before dumping a 50/50 mix of coolant into the engine.  After about a minute I heard the disheartening sound of coolant seeping out below the EV.  Thankfully, I still had the catch pan underneath.

When I looked underneath, I could see that it was pouring out from one bolt.  My initial thought was that I didn't tighten the bolt as well as I should.  Unfortunately, now the lower hose was blocking access I needed to tighten the bolt.  I could made a decision to completely drain the coolant to tighten the bolt but I decided that it would be better if I simply loosened the lower hose, pulled it down a little to get access to the bolt.  This was messy.  I had gloves on but I could feel some splashes from the coolant as my hands would get in the way of the stream.  At one point, I got a drop on my lip and another near my eye.

Unfortunately, no matter me trying to tighten the bolt, the stream didn't abate.  Finally, I went ahead and removed the lower hose and let the coolant drain into the catch pan.  This is where the real adventure began.  While I was trying to loosen one of the bolts, I lost my 10 mm socket in an underpart of the engine.  One that I have named, "Adolf Der Parts Muncher."  

Adolf Der Parts Muncher.  Right above my finger and back is a small area that can catch parts.

What ensued from there was frustrating and comical.  I found myself in a Catch-22 situation.  I needed the 10 mm socket to remove the housing and I needed to remove the housing to retrieve the 10 mm socket.  I worked back and forth using a 10 mm socket that was made to work in a screw driver but the angle didn't allow me to use the screw driver.  I finally found success using my 10 mm wrench, running my hands above the wiring and then moving the wrench millimeters at a time until I could finally loosen the bolts enough to use my hands to fully remove them.

Once the housing was out, I spent about five minutes trying to figure out some sort of tool to remove the 10 mm bolt which seemed to be perfectly fit within the jaws of Adolf.  Finally I used the short extension, and after a minute or two, got it inside of the socket and pulled it out.  That wasn't before I found another 10 mm bolt in Adolf's ravenous maw.  It turns out that some previous owner had lost one of the 10 mm bolts to Adolf when they replaced the thermostat.  They probably never knew where it went and imagined it to have traveled to an alternate universe where it was living it's best 10 mm bolt life.  

It was time to pull the thermostat out.  Upon inspecting the thermostat, I noticed that there was a chunk in the o-ring.  I don't know if it was there when I received it or if maybe my awkward bolting created the chunk when I installed the new thermostat.  Again, it's important to inspect before installing a part.  With not much options, I decided to use the old o-ring.  It looked a little thinner than the new one but it sat perfectly on the new thermostat.  I used a little RTV that I borrowed from the neighbor as I couldn't find my RTV. 

Chunk out of o-ring.

 

Bolting up the thermostat the second time was actually easy.  I had gone through the learning curve of which tool worked best.  Once I had everything tightened up, I was finally back to where I had been over an hour before -- filling up the reservoir.  This time, I used a water bottle and just filled it up with distilled water.  The first went in and I waited -- no drip.  I added a second -- no leaks! -- I added a third, still no leaks!  To keep the mixture right, I added three water bottles full of concentrated antifreeze.  After I felt confident nothing was leaking I filled the reservoir up with a 50/50 mix.  I started the engine to let the air bubbles work their way through and to further test the system under pressure.  No leaks!  I capped that sucker and was done.  Total time about 2.5 hours.  I didn't even have time to test it, nor did I have time for a shower.  I gave my hands a quick wash, threw my trusty Quiet Flight hat on and we were off to play putt-putt.  

It's been a couple of days later and I've had a couple of chances to test drive it and to also let it sit at idle.  The new thermostat seems to have solved the issue.  The temp gauge, when I am driving sits either right at the 1/2 way point or just a little over it.  The fan clicks on when it gets hot and more importantly, clicks back off when it drops.  With the old thermostat, the fan was constantly running when the engine got warm.