Took the ES back for a second day of autocrossing. After my forth run I pulled back into the grid, took off my loaner helmet and returned it to the front of the line. Upon walking back I noticed a pool of coolant under the front of the engine. It was not a blown hose - not good. It was a good thing I brought a trailer.
I got the car home and since it has cooled off I start looking for the leak. I note that when I squeeze the lower hose coolant leaks down the timing gear cover from the front of the engine. Ok, I might get lucky, maybe a blown water pump seal. I pull the fan and pulley bell - no leaking out the weep-hole. The leak isn't from the seals between the pump and the head, nor the heater return pipe or the lower hose pipe seals. So it is either a blown head gasket, cracked head/block or blown water pump gasket.
I have a spare new pump and gasket/seal kit. So I pull the pump. The gasket tears upon removal of the pump - not diagnostic but a promising development. Also some of the gasket looks to be missing, since I am working on the trailer it isn't in the gravel. The other thing I not is that two of the bolts are very rusty, especially on of the short ones from the left side. I clean everything up and look for my gasket varnish - I found the little bottle - I amaze myself sometimes.
I cross my fingers and decide to replace the pump with the rebuilt one. If I still have a leak then something else blew. Before replacing the bolts I take them to the wire brush wheel on the grinder. I clean up four bolts - three long and one short. When I go back for the fourth bolt it is very rusty with it's threads full of gunk and rust. Only about a thread and 1/2 looks used. I check the marking and make sure I have the right bolt - again I dropped it but since I am on the trailer there is just the one bolt and washer. I check the markings, grade 5 bolt but it has different markings than the other three. Then I note that it is shorter than the other short one.
I almost go over to the B18 engine sitting on the stand an remove the bolts from it's water pump - same water pump.
So now I have five bolts for four holes and only two match. One 2 inch, two 1 3/4", one 1 1/4" and on 1". Ok the 2 inch bolt holds the lower radiator hose pipe, the two long bolts are for the top of the pump and the 1 1/4" bolt holds the heater pipe to the pump and the 1" for the left side. No that cannot be right the heater pipe mount is no thicker than a washer - 16 guauge steel, not 1/4 inch difference in length. Now all the bolts but the 1 inch bolts have the same grade markings, then I note that the 1 inch bolt just barely has 2 threads sticking out of the pump housing.
So I do a quick RCI in my head.. Leaking coolant caused by blown water pump gasket -> excessive reving over presurizes the cooling system -> caused by 1st gear out of the Chicago box to the finish where the engine is likely at or a bit over redline (ok not good but if an engine cannot take a moment at redline then something is wrong). The car was not running hot - right on the first line - normal operating temp so it is not an overheating issue. What caused the gasket to leak? Lack of torque caused by only two threads of a short bolt into the block? I didn't measure the torque of the bolts as I removed them but that is my assumption, especally juding from the rusty gunky condition of two bolts - the long one and the 1 inch one from the same side of the engine.
Historical note - I have been fighting a coolant leak from the left side of the engine - right around where the head meets the block - leak down test a few weeks ago ok, not the head gasket. I have replaced fixed radiator cap seals, overflow tank relef cap and check all the hoses - it is either the pump seal but it doesn't leak at idle. Small leak but enough that I must keep an eye on the level to be safe every few hundred miles.
So I cannot prove without reinstalling the short bolt that it caused the problem but I assume it is the root cause of the leak. Now I have some grade five 5/16 bolts in my supply but only 1 inch (grade 2) 1.5 inch, 2 inch and 2.5 inch. I thread two nuts on to lock the length at 1.75 and cut a 2 inch bolt down to size.
Once I coat the gasket in gasket sealer I put the seals in the pump and install. I fit the heater pipe seal and the seal on the lower pipe as well. Ok everything torques down quite well (no I didn't pull the spects and I should have or use a torque wrench - the sun is down and light is fading fast.
The moment of truth - By now it is full dark and I have a stand light when I fill the radiator and tank. Without installing the fan clutch or fan I start the engine to see if it still leaks. After a minute no leaking so I shut the engine down so it doesn't get too hot yet.
It takes a while to swap out the fan clutch and move the fan to a used one but finally everything is back together. I didn't drain the block as this car has a coolant sensor where the petcock is on the B18 and B230 engines but I did drain the radiator and most of the head by pulling the heater core hose (also drained the heater core too).
I start the car up and open the heater valve to full heat - after 15-20 minutes things start to warm up and NO LEAKING!
So my goal to learn how the car handles when pushed was more or less achieved and I identified a weak spot that I had been chasing down for the last 9 months. So I guess I will take her out to another autocross to get some more experience.
So I missed my last run today because someone was too lazy and did find or make the correct size bolt for one they lost when replacing the water pump. I will note that a 1.5 inch bolt would bottom out before tightening the pump to the block. Good news was it happened in a controlled environment where I was able to get the car on the trailer without running it again. This could have been bad had it happened on the open road and I lost coolant with a hot engine - sure it was leaking but the block and head remained full.
