So some two weeks ago I ran across some problems with the engine. This was actually rooted from the very first time I turned on the new engine where the temperature gauge began to creep after about 10 minutes. Long story short it turned out to be a faulty thermostat which was brand new at the time.
That was only part of the problem.
So two weeks ago the overheating problem got pretty bad where the gauge remained 3/4 of the way to "H" even while driving. So when we stopped to top off the radiator we noticed that there was oil in the coolant. Allot of it. I drove the car back home where it stayed until today.
On Friday we took the head off only to notice that the rear (closest to the fire wall) dowel pin was loose and barely on the block. The front dowel pin was missing. Ther's yur problem. At least the one associated with oil in the cooling system. When we looked at the bottom of the head we noticed the front dowel pin embedded in its bore with barely any of it protruding out of the head's surface. Without dowel pins the head can actually "walk" on the surface of the block at high rpms/vibrations. This explains why there was oil in the coolant but no coolant being burned.
I missed this the first time I installed the head simply due to inexperience. I actually remember seeing the dowel pin in the head and not giving it a second thought. it just looked like some oil passage feature
![LOL :lol: :lol:](/wp-content/themes/gtp16/images/smilies/lol.svg?v=3)
Same goes for the rear dowel pin where I should've made sure that it was securely tapped into the bore.
So it appears that often the front dowel pins stay lodged in the head when they're removed for the first time. This explained why my 03 block didnt have one and why the 99 head I got had one lodged in its bore. Btw, I remember there not being a front dowel pin in the 03 block when I first removed the 03 head (I just didn't know there was supposed to be one there
![Dunce :dunce: :dunce:](/wp-content/themes/gtp16/images/smilies/dunce.svg)
) So we were pretty certain that that was the problem.
Another thing about the 99 head that I didn't really pay attention to when I got it was that whoever had it before me (either the guy I got it from or the guy who owned it before him) took a pneumatic sander to it in an attempt to clean all the gunk off of it. You can tell because of all the swirl marks on the head (the same swirl marks on the embedded dowel pin which proved that it belonged to the 99 head and not the 03 block) which also showed that he used too coarse of a grit. Sigh.
Sooo, we took the head to a motorsports machine shop and found that it was slightly "warped" at the #4 cylinder. The guy took off about 4000s and cleaned everything up. Great overall job. I installed the head yesterday only to find out that the temp gauge was STILL creeping after around 15 minutes of idle. I felt the upper hose and it was cold. This was the same thermostat that I bought when I first did the swap. It was one of those dual core ones and cost me like 24 bucks. POS. I bought a new one, installed it today, let the engine run. The upper hose got warm while the lower one stayed cool. Problem fixed.
Finaly.
I also got a proper overflow tank. Pretty much the only one available for the NA Miata.