This weekend my friends and I did some valvetrain upgrades along w/ an ITR mani and CTR TB. I also changed the timing belt and tensioner as well as the upper and lower radiator hoses. Now the car, a 99 Civic Si w/ a B16a2, is overheating. I just got back tonight from my friend's house and found a small leak coming from a nipple on the mani that we tried to block off. So I am getting pressure loss as well as a steady drip. I will fix that in the AM. Tonight I also discovered that THE LOWER RADIATOR HOSE IS COLD !!! Does this mean that the thermostat has gone bad?? I will check it in the morning, but I wanted some opinions tonight to help me out in the morning. What exactly is the path of the coolant in this type of car?? Thanks

 

the flow goes from top of radiater to bottom. if your cars been running a while, but the top hose is not hot, then you need a new thermostat...

 

he said the lower raditor hose isnt hot. if you got a coolant leak, that could most likey be the problem. find it and fix it. how much fluid did you have left in your radiator?

 

OK, I found the coolant leak, I will be fixing it this morning. It is the small brass nipple on the ITR mani next to the bigger one that loops to the head. We didn't use the small one. But it is SO SMALL, could it really have that big of an impact??? And why isn't my lower radiator hose hot like the upper??
Thermostat??

 

Your upper hose is hot and your lower one is cold????????
Is your water pump spinning backwards???????
If your T-stat was sticking your top hose wouldn't get hot.

 

Exactly !! Hot upper, cool lower.
The leak is fixed, but I don't really want to start it yet...

The Timing belt and tensioner were changed over the weekend, but the dealers didn't have a water pump. There are no signs of leakage from it, or anywhere else.

The ignition timing is set to 17 degrees BTDC.
I refilled the radiator this AM.

Is the following correct??Flow goes like this: Cylinder head-->upper hose-->radiator-->lower hose-->thermostat-->block
Is this right???

 

NOPE, it goes: (Gets hot in the block and head) HEAD > THERMOSTAT > UPPER HOSE > RADIATOR > LOWER HOSE > BLOCK > HEAD...

 

OK, so as the head heats up, the thermostat opens to allow coolant flow back into the engine from the radiator, right??

And I found the leak, a small nipple on the ITR mani. that I didn't use on my B16a2. The clamp we initially used was inadequate. I switched to a hose type clamp and it sealed it up like a champ.

Thanks