overheating --i need fresh ideas not the same old stuff

[GINA2MR2]

1991 NA
5sp
120k
mods-
GTO pedals
K/N cold air intake off 5.7 camaro
dump style exhaust
toms style scoop
strut bar (rear)
no AC system
14"16"18" wheels i run the 18s right now
ETCETC
Stock engine- stock plugs and wires
I added a rear fan in the engine bay to cool it

My car will drive fine for weeks then all the sudden the coolant will be gone. The reservoir will go from full to empty suddenly. Then it will start to heat up. I always shut it off if it even hints of overheating

---
I'm thinking there might be a head gasket issue. I have not had any trouble with the head gasket before. Another possibility is the water pump.

I'm really looking for fresh ideas OTHER then bleeding the system, check hose clamps, and the regular initial troubleshooting techniques.

--
heres what ive done so far
-
new thermostat
removed radiator-flushed
flushed entire cooling system
flushed water jackets (i did this when thermostat was replaced)
new 'radiator' cap
replaced all hose clamps with worm style and replaced hoses that seemed to be less than amazing condition haha

- engine performance-
gets good mpg
has great power, no loss anywhere.
doesn't smoke or burn any oil
oil comes up clean and i recently replaced the valve cover gasket and plug seals
there was no sign of antifreeze in the valve cover (very clean)
-

Thank you.

[Gairloch]

I think you've got the right idea. Coolant, when it leaves, either drips on the ground or goes out the tailpipe. If you're not seeing it under the car then it's not the water pump.

The HG can be blown without the coolant showing up in the oil, especially if it's a rather small hole. I wouldn't expect a compression test to show anything since the engine is still running well but a leakdown test would prove it.

[jholder]

I seem to recall that you can have the coolant tested for the presence of hyrdocarbons, iirc that would indicate a headgasket leak. That might tell you if there's any problems with the HG.

[GINA2MR2]

excellent stuff guys thanks
the burning of coolent - the car never has a puddle of anything under and the exhaust has no trace of coolent burn-
i do a lot of work on mopars at work and i know coolent burn smell haha

[mr2tim]

Hi Gina,

You want a fresh idea? Here goes.

I've had this problem before, as I've owned and competeted for 20+ years.

You may have a tiny hose/componet leak which, apparently from your given timetable, takes many days to realize.
(My last one was my NA street car which had a pinhole leak at the water fill pipe where it meets the entry to the cylinder head-was that ever hard to locate!!)

What happens is that the problem area leaks very, very slowly and to compound the problem it does so only when the the system is hot and thus pressurizing the cooling system. Your coolant apparently drips onto HOT parts of the car and evaporates, bingo, no trace?

Look for areas underneath clamps, where cooling componenets touch other items in the engine compartment, undercar coolant tubing and radiator. There's about 25 ft of coolant tubing to and from the radiator so there's LOTS of places to look.
Yes. most is under the car, sorry!

I'm not discounting the other other comments given here, they may be valid.

mr2tim
Supercharzed Toyz Raczing
A Toyota Race Team since 1989

PS Your a girl you can dig this?
My wife blows talcumm powder into inaccessible areas and if it gets wet that's the leak.
(she's a great pit crew chief)

[mrjimmyx]

does it loose fluids when car is on or off? if off, I'd pour water in it and turn it on and let it sit for 10 mins and check every now and then for leaks. What i did was put card board underneath everything and listened for drips and and moved stuff around to see if any hoses were cut. cheap way for find out coolant leaks.

[Mister2.2]

1. UV Dye + Blacklight.

2. Have it pressurized and monitored for pressure loss.

[Oteck]

fresh idea? how about dump that sorry excuse for an engine for something w/ actual power? lol jk

have you removed the underpanels, you may have leak deep inside the body so it's hidden

[GINA2MR2]

i have removed the under body panels but will go back there and remove them again.
it wont drip at all hot or cold.
haha im a dude not a chick
but nice try jk
i will try this stuff and see what i get

[mr.ac]

I'm putting my money on the water pump. the seals are going out. it should be leaking from right under the pulley. look at that area while the car is runing.

[Gairloch]

Getting a hydro-carbon test is where I would start. Would be less expensive than a leakdown and tell you all that you really need to know. A leakdown is helpful if you care about which cylinder it is but with a BHG it really doesn't matter.

[GINA2MR2]

no leaking under the water pump,
no leaks under the panels under the body
time for the leak down test.
haha im thinking about dumping the motor i got but b18tuner wont part with his old turbo motor haha so ill prolly keep what i got or try to score a turbo block from work .. i already got about 3 turbos chilling on my desk to choose from haha, so idk.
ill see what i got