coolant evaporating?

FastCAD

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I am having a problem as to where my coolant is going to?
a week ago the check coolant light came on but it did not overheat.
I immediately refilled with a gallon of coolant and continued on my way.
the next day I checked the cold radiator and overflow bottle both
appeared to be empty. I refilled again and brought the engine up to
normal operating temp with the rad cap off to start my search as to
where the coolant went. There was no leak anywhere ie; thermostat,
water pump, hoses etc. I then looked in the rad neck and expected to see
a coolant stream but did not see any significant movement. I figured that
my thermostat may restricting coolant flow. changed my very old failsafe
thermo. for a new failsafe unit. car runs normal but coolant is still disappearing.
I now think that the coolant is burning off internally but I can't tell if it is a
radiator problem or my water pump has silently failed?
can anyone shed some light on what is going on or point me in the right direction
for repairs?
thanks
ps. with the rad cap off and coolant in the neck and at normal temp the coolant will continue to burp air and go down slowly.
 
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luigisho

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Any in the oil? Any smoke out exhaust? Any coolant on the ground?

It's either leaking via hose or cooler (radiator/heater core), head leak (into oil or into cylinder), ineffective cooler or hoses leading to overheat of fluid, waterpump not moving enough coolant..
Are you sure it's not leaking outside the car? These things can leak and drip and whatnot alot
 

FastCAD

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Any in the oil? Any smoke out exhaust? Any coolant on the ground?

It's either leaking via hose or cooler (radiator/heater core), head leak (into oil or into cylinder), ineffective cooler or hoses leading to overheat of fluid, waterpump not moving enough coolant..
Are you sure it's not leaking outside the car? These things can leak and drip and whatnot alot
I have had a week to look for any leaks. none. car runs normal but coolant burns off but I don't smell anything either??
I have developed a rear main seal leak but it is only oil and I have a date for a new clutch and seals next week. I have checked the oil and around the lower block but no leaks except the rear seal and no sign of water intrusion.
After about 150mi. I get nothing but vapor from the rad and bottle.
The water pump has no leaks but I have never seen a bad wp that didn't leak or make some noise but it is way too quiet for me. The radiator is "old stock" and if I could some how check that it has good flow it might narrow it down to the wp or maybe just replace both???
thanks
ps. heater works well and no hose leaks from there either.
 

luigisho

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I wonder if t-stat, wp, or collapsed hose might be trapping but the coolant temp sensor isn't triggering a light. potential hg fail, crack in head or block but this is not showing alot. Is there rough running?


Maybe some exhaust gases leaking into coolant? a little over 1/2 way down below valves pic
 
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FastCAD

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luigi;
thanks for the leads. my local parts suppliers don't have a test kit to buy or borrow.
I can't imagine a yamahammer with a "cracked block" not leak or blow smoke and a "blown" head gasket that would allow this engine to run like a scalded dog.
I do think a "blown" head gasket would show up on a compression test and a I do have a comp. tester. I will do this test and let you know.
come monday I will try to get a rad shop to perform a blown gasket/cracked block test. there is no coolant in the oil. the dip stick is clean and actually shows about a 1/2 quart low from the rear main seal which I have been collecting with a drip pan and there is no coolant there either.
I had hoped that someone had experienced something like this before but that is o.k. I'll find it and let you know.
thanks again!
 

rubydist

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I have had this happen on a couple of the SHOs that I have owned. The first one was due to a small leak in the thermostat area where it dripped on the top of the block and would evaporate so none ever dripped on the ground. I only found it be happening to open the hood with the engine warm and seeing that the top of the engine was warm. The second was due to a small leak in the overflow bottle and was a similar thing - it dripped onto the metal in such a way that it evaporated before it dripped on the ground.

I recommend you drive it 10 minutes or so to get it fully up to temperature and open the hood with the engine running and carefully look for a wet spot.
 

FastCAD

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no cracks in the coolant bottle?
thanks for asking. no
the bottle stays full until the rad runs down the coolant, then the reserve bottle sends it to the rad just as it should.
the sho has been running this way all this week with no problems other than adding coolant every morning. lol
it seems that either the rad has restricted the flow or the water pump is not working
so the coolant just sits until it reaches the boiling point and evaporates creating a void where the rad "burps" and the coolant goes down so on and on.
the "fail-safe" thermostat MotoRad #7270 saves the day by not allowing the thermo to fail in the closed position. very clever and "patented".
I will replace the rad it is 30yrs. old, the fan is fairly newer and working correctly but I'll keep my fingers crossed that it's not the water pump a definite p.i.t.a.

ps. if anyone can find me a '91 'taurus gl stock rear bumper' I will pay a finders fee.
yours truly,
joe
 

FastCAD

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I have had this happen on a couple of the SHOs that I have owned. The first one was due to a small leak in the thermostat area where it dripped on the top of the block and would evaporate so none ever dripped on the ground. I only found it be happening to open the hood with the engine warm and seeing that the top of the engine was warm. The second was due to a small leak in the overflow bottle and was a similar thing - it dripped onto the metal in such a way that it evaporated before it dripped on the ground.

I recommend you drive it 10 minutes or so to get it fully up to temperature and open the hood with the engine running and carefully look for a wet spot.
will do
thanks
 

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Put your zip and car info into the search. It lists a few cars to choose from. Might have to drive or get shipped. Find the model years that are compatible. I know 89-91 should work but maybe back to 86 for non SHO vehicles?? Not sure
 

Irish Pride

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The car would overheat and boil over if it were getting that hot. It's a closed/sealed system so the coolant can't just evaporate out of the system. You would get boil over out of the cap and into the overflow bottle.

Go rent a pressure tester at O'Reillys or Advance. They all offer them. Pressurize the system and if it doesn't hold 16psi, you have a leak somewhere. The pressure from the tester should point you to the leak if there is one.

-Chad
 

FastCAD

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Put your zip and car info into the search. It lists a few cars to choose from. Might have to drive or get shipped. Find the model years that are compatible. I know 89-91 should work but maybe back to 86 for non SHO vehicles?? Not sure
thanks Luigi.
The bumpermegastore does not exist anymore. only their online listing was not removed. I tried recently but there is no contact but it's the thought that counts.
the carparts link is rough and I am still working it. the junk dealers are pretty lazy and the one I talked to so far in PA can't even verify or is unwilling to find out if the part even exist in some remote lot and he wanted me to pay for it unseen and in advance before he would search and I still had to make plans to pick up.
carparts list another in GA about 1200mi round trip for me that I am considering but I haven't contacted them yet because I'm still trying to get over the guy in PA. lol. there seems to be a few others but for me they are pretty remote but there is "shiply" online that can provide pick-up and delivery for a pretty price. I found a new re-man unit (last one) in Irving, TX on e-bay but lost out because I had a $1,000 tied up in two sham companies that could not produce the part after I did a "BEWARE OF THIS ONE" (national parts search database online) after two months credit payments were returned but it was too late for the 'last one' at e-bay.
I have resorted to searching private listings of whole cars selling for $500 and taking the bumper then hauling away the rest. I can save some money and use it for therapy to get over my need to own a SHO. lol
joe
 

FastCAD

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The car would overheat and boil over if it were getting that hot. It's a closed/sealed system so the coolant can't just evaporate out of the system. You would get boil over out of the cap and into the overflow bottle.

Go rent a pressure tester at O'Reillys or Advance. They all offer them. Pressurize the system and if it doesn't hold 16psi, you have a leak somewhere. The pressure from the tester should point you to the leak if there is one.

-Chad
h'mm. I don't get boil over but I will have the rad pressure tested come monday.
the dash temp gauge never went into the red regardless of conditions even when the check coolant light came on. what's odd is that with a leak of coolant I would easily be able to smell it.
I will advise anything I find.
Thanks
 

luigisho

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I have had fairly good luck with the salvage yard stuff but so far I have been able to get stuff within driving distance (not short but doable) and junkyard people are not the most accomodating folk for sure. Sometimes you get lucky and they are great. crap shoot. The old cars are getting thinned out for sure. good luck.

Watching the coolant thing. Totally agree. get the whole thing pressure tested until you find it.
 

FastCAD

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Thanks to all for their help and suggestions.
This forum is one of the best things when you are dealing with the SHO.
One thing I've learned is that if you have a problem then usually someone else has already, bin der dun dat.

I woke up this morning from my SHO delerium and was more realistic.
I am dealing with a 30 yr. old rad and it's about time to replace it so I ordered a new stock unit and install kit from SHO Source knowing that I will get genuine oem parts.
Thanks again to everyone.
 

luigisho

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evaluate the hoses if they are old. they are made of degradable material flowing chemical laden fluids that can degrade rubber compounds. good luck. These things are maintenance hogs by original design compounded by age.
 

FastCAD

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evaluate the hoses if they are old. they are made of degradable material flowing chemical laden fluids that can degrade rubber compounds. good luck. These things are maintenance hogs by original design compounded by age.
I found my coolant leak.
I took all the advice from the members. Evaporation was out and "there had to be a leak somewhere".
The sho was cold and the rad was full. I started the sho and let it idle while I went into the house. I came out and the sho was fully warmed up and the temp gauge was normal. I made a short drive and when I came back the driveway had a good run of coolant. I checked the two short rubber connections to the heater pipes just behind the thermostat under the intake. There it was lightly dripping on the top of the bell housing and not enough time to run off.
This area is tuff to get to from on top but the sho is going in for a new clutch & rear seal and may be easier to get to from underneath.
Thanks to all.
 

Irish Pride

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With the airbox and throttle body removed those hoses are way more accessible. I would replace them all at once. Odds are they are all in need of replacing and the leak will just move to the next weakest one.

-Chad
 

FastCAD

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With the airbox and throttle body removed those hoses are way more accessible. I would replace them all at once. Odds are they are all in need of replacing and the leak will just move to the next weakest one.

-Chad
Yes. Will do. Thanks.
Does the ecm temp sender need to be tightened all the way in? It is very tight now and a couple of threads are still showing. I don't want to force it against the alum.
 

Irish Pride

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Yes. Will do. Thanks.
Does the ecm temp sender need to be tightened all the way in? It is very tight now and a couple of threads are still showing. I don't want to force it against the alum.
No, it's a pipe thread so when it stops turning its done.

-Chad
 
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