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

GINA2MR2 · 09-19-2009, 12:49 AM

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 · 09-19-2009, 12:54 AM

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 · 09-19-2009, 01:05 AM

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 · 09-19-2009, 11:04 AM

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 · 09-19-2009, 11:24 AM

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 · 09-19-2009, 01:48 PM

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 · 09-19-2009, 02:40 PM

1. UV Dye + Blacklight.

2. Have it pressurized and monitored for pressure loss.

Oteck · 09-19-2009, 02:43 PM

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 · 09-19-2009, 02:56 PM

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 · 09-20-2009, 01:06 AM

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 · 09-20-2009, 02:08 AM

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 · 09-26-2009, 04:39 PM

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

09-19-2009, 12:49 AM	#1 (permalink)
GINA2MR2 Not A VR6 Join Date: Dec 2007 Location: J-Town Posts: 329 Thanks: 3 Thanked 7 Times in 7 Posts iTrader Rating: (0/0% )	overheating --i need fresh ideas not the same old stuff 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.

09-19-2009, 12:54 AM	#2 (permalink)
Gairloch Dreaming of apexes Join Date: Aug 2005 Location: Minneapolis, MN Posts: 4,854 Thanks: 125 Thanked 258 Times in 228 Posts My Google Map iTrader Rating: (7/100% )	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. __________________ "Inside the car, the world beyond the driver's immediate horizon ceases to exist. Alone with the solitude of his desire, survival sense numbed by the speed, he's outrun the mediocrity of the outside world, slipped the shackles it tries to clamp on us all. He is running free, chased only by a fear of failure, for failure is to risk ejection into the real world." ~Mark Hughes

09-19-2009, 11:24 AM	#5 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 690 Thanks: 2 Thanked 41 Times in 38 Posts My Google Map iTrader Rating: (2/100% )	The unsee-able leak? 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)

09-19-2009, 02:40 PM	#7 (permalink)
Mister2.2 Cheese it! Join Date: Feb 2005 Posts: 6,274 Thanks: 108 Thanked 109 Times in 94 Posts Blog Entries: 1 My Google Map iTrader Rating: (3/100% )	1. UV Dye + Blacklight. 2. Have it pressurized and monitored for pressure loss. __________________ --Josh MR2Trader.com Free Accounts to Buy and Sell your MR2 Parts! Ask me about Web Hosting Solutions, starting at $5.95 a month. 'I am at two with nature.' 'Students achieving Oneness will move on to Twoness.'

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09-19-2009, 01:05 AM	#3 (permalink)
jholder I put the ho in 'hosale Join Date: Nov 2007 Location: Huntsville, AL Posts: 444 Thanks: 8 Thanked 14 Times in 11 Posts iTrader Rating: (2/100% )	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.

09-19-2009, 11:04 AM	#4 (permalink)
GINA2MR2 Not A VR6 Join Date: Dec 2007 Location: J-Town Posts: 329 Thanks: 3 Thanked 7 Times in 7 Posts iTrader Rating: (0/0% )	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

09-19-2009, 01:48 PM	#6 (permalink)
mrjimmyx Cage Fighter Join Date: Jul 2009 Posts: 191 Thanks: 3 Thanked 8 Times in 8 Posts iTrader Rating: (0/0% )	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.

09-19-2009, 02:43 PM	#8 (permalink)
Oteck RAAAGE! Join Date: Aug 2005 Posts: 2,151 Thanks: 8 Thanked 60 Times in 57 Posts Blog Entries: 2 iTrader Rating: (3/100% )	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

09-19-2009, 02:56 PM	#9 (permalink)
GINA2MR2 Not A VR6 Join Date: Dec 2007 Location: J-Town Posts: 329 Thanks: 3 Thanked 7 Times in 7 Posts iTrader Rating: (0/0% )	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

09-20-2009, 01:06 AM	#10 (permalink)
mr.ac Just Say NO to Snorkes Join Date: Nov 2008 Location: Central Coast, CA Posts: 329 Thanks: 0 Thanked 15 Times in 15 Posts iTrader Rating: (1/100% )	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.

09-20-2009, 02:08 AM	#11 (permalink)
Gairloch Dreaming of apexes Join Date: Aug 2005 Location: Minneapolis, MN Posts: 4,854 Thanks: 125 Thanked 258 Times in 228 Posts My Google Map iTrader Rating: (7/100% )	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.

09-26-2009, 04:39 PM	#12 (permalink)
GINA2MR2 Not A VR6 Join Date: Dec 2007 Location: J-Town Posts: 329 Thanks: 3 Thanked 7 Times in 7 Posts iTrader Rating: (0/0% )	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