Arcolithe

so it took me a while to understand what was happening with my coolant.

I let the car sit on concrete all day, peaked under and saw no wet spots. However I noticed my coolant dropped about a quarter of a gallon. My engine was just recently rebuilt and I need to diagnose a few things before I start thinking he didn't do something right.

For the water pump, is the pulley supposed to be very loose? I can turn the pulley with my index finger while my car is off. The belt will stay in place as well.

I recently deleted the thermostat lever so that it's a solid flow, was having hot issues before and that fixed it. could that cause some issues?

the cap for the reservoir pops off very easy, but at the same time it "bubbles" when the car is hot. should there be a rubber sealant or ring under the reservoir top? this cap seems to "burst" when I rev my car 5-8k




12A N/A with edelbrock 600 and smaller secondaries.
P.S. no clouds of white smoke at start, sometimes a thin vapor of grey. but you can never notice it while driving.

KansasCityREPU

iTrader: (9)

Rotary's have an internal water pump housing bypass. Unlike many older cars, you must run a thermostat or do what the race guys do and plug the passage that gets closed when the thermostat is open. I'd suggest getting an OEM thermostat.

Based on the symptoms with the bubbles and losing coolant, I'd say you have an internal water seal that is bad. I had something similar where engine compression was back feeding into the cooling system and pressurizing it so much that the overflow tank would shot water out the tiny hole in the cap 30 feet across the garage.

It could also be an intake o-ring.

Siraniko

iTrader: (13)

Nah for street cars, you dont need to plug the by-pass...motor will live . In fact, my other 13-B streetport (has +\- 100k miles of daily abuse) has a RX-4 w/p housing where the by-pass has multiple tiny holes instead of one large 3/8 size hole. In addition, i use a gutted t-stat instead of t-stat less.


Now back on his problem. SOP is to rod-out the radiator when you have newly rebuilt motor or shop will void the warranty. W/P shouldnt have a play. Double check the w/p pulley 10mm bolts, maybe the bolts are loose causing the pulley to have a play. Start with the obvious also such as rad cap.

diabolical1

iTrader: (3)

you mentioned it's recently rebuilt. i think it's one of the water seals. they are sneaky little buggers. they don't always smoke consistently or profusely, if at all. they don't necessarily affect starting either. however, if you're losing antifreeze and see no signs of external leaks, it's very likely a coolant seal. the pressure and bubbles are telltale, but even they don't happen all the time.

LongDuck

And... if it's a coolant seal (internal engine), then you need to get it back to whoever rebuilt it in the first place, because it may still be under their limited warranty. Good luck,

DriveFast7

iTrader: (1)

Compression gasses passing thru a pinched water seal, over pressurizing the cooling system thus the bubbles and pop in the coolant overflow tank. Da motor, it must come apart. And plug that bypass port in the water pump housing witha 1/2" NPT plug and red loctite.

Arcolithe

for the thermostat, just replacing it with a $10 OEM one should also be fine right? It seems to have a mechanical function.

if it's a coolant seal, it's not an easy as taking off the intake manifold and checking it there? it would be located in-between the housing?

and would small flakes of minerals (Everytime I fill the radiator, a little bit pops up) be causing the problem? I'm trying to figure out if there's a guarantee way to tell the mechanic who built the engine that it's leaking coolant.

Arcolithe

I don't want the mechanic to tell me that my radiator causes the coolant leak because I never replaced it. He didn't recommend me to replace the radiator since the car was fine and peppy when it was given a month ago.

diabolical1

iTrader: (3)

a busted/leaking radiator can't let combustion pressure into the system. so don't let him try to convince you otherwise. the seals at the intake manifold can't leak into the chambers either (unless you're REALLY unlucky and there's a serious crack in the housing).

when the car is cold (like after it's been off for the night) check the chambers. the exhaust ports are the only openings large enough that i can think of. turn the engine by hand and if the leak is bad enough (sounds like it is if you lost a quart in a day), then it'll probably just run out onto the floor. if not, stick a paper towel in there and see if it soaks. just remember to check both chambers.

i'm not sure i understand what you're asking about mineral flakes ....

erick31876

iTrader: (8)

it sounds like you definitely have a bad coolant seal,as for the mineral flakes it sounds like somebody has put some kind of stop leak in the radiator.I would definitely take your car back to whoever rebuild it and while you're there get a new radiator or at least flush the hell out of it

Arcolithe

I will take a picture in the morning, as for the coolant seal, the only way to check the coolant seal is between the housings? or are you guys referring to another coolant seal where the coolant connects to the engine?

as for the thermostat

"Rotary's have an internal water pump housing bypass. Unlike many older cars, you must run a thermostat or do what the race guys do and plug the passage that gets closed when the thermostat is open. I'd suggest getting an OEM thermostat."

Which passage would be plugged? and why would it be plugged? I figured by having it completely open the coolant would circulate around easier. The purpose of that thermostat is to prevent coolant around the engine when it is cold so having coolant while the engine is cold would only delay the warm up of the car during start?

luiml73

iTrader: (1)

The only way to check the coolant seals, is by opening the engine. What diabolical1 is saying, is to first remove the header and turn the engine by hand to see if any water come pouring out the exhaust holes.

Banzai Racing; Damaged RX-7 Engine Components

read this

https://www.rx7club.com/new-member-r...l-leak-948179/

DriveFast7

iTrader: (1)

Ask the mechanic to put a coolant system pressure tester in place of the radiator cap. Pump it, watch the pressure drop, and ask him to find the leak. WHen you don't see coolant coming out of the cooling system anywhere , and the pressure drops, ask him where the leak is. If you then take the header off and turn the motor over by hand eventually coolant will come out of the exhaust port....

Arcolithe

thanks, good advice to corner my mechanic into the rebuild being the problem.