my vette has a 160 stat and tpis chip that turns the fan on sooner. my over flow reservoir shows completly full when the car is stone cold. when im driving to work the temperature gets to about 158 and the low coolant lite comes on. if i drive a little farther, the temp goes up to about 165 and the coolant lite goes off. whats the problem?

 

I had this problem on my 89 vette about 6 years ago..

I would fill the radiator.. drive the car for 1/2 hour or so and the low Collant light would be on.. and the Reservior was full. Leave the car over night.. Reservior was still full..

My problem ended up being 2 Blown head gaskets.. Both at the back of the heads..

 

When the engine cools off it should suck water from the resevoir, and keep the system full. Jeff's situation as a definite possibility. The second thing I would do is pressure check the cooling system. If it won't hold pressure, you need to find out why. The first thing I would do, is check your radiator cap. If it doesn't open under vacuum, the resevoir can't refill the radiator. I hope it isn't head gaskets, but... Good luck.

 

if it was head gaskits wouldnt it be leaking somewhere?

 

i just called a mechanic friend of mine. he said if the head gaskits are leaking i should have water in the oil, i checked and thats not the case. im going to change radiator caps and see if that solves the problem. their isnt any vacume when i open the cap. cross your fingers :yesnod:

 

wELL. . .I'm a mechanic friend of yours and I say this;

If you've got a blown headgasket ,water doesn't necessarily get in the oil.

The leak COULD be from the combustion chamber to the water jacket.
NO water in oil if you have this one.
You may notice you need to keep adding a little water but there doesn't seem to be any leak.

These are usually tricky to find because they don't open up until the engine is hot and then all you have is a little water consumption.
Hard to find sometimes.

The gasket COULD have failed from the water jacket to some point outside of the block.
In this case you'd find water under the car.
STILL no water in the oil.

The gasket could have failed from the combustion chamber to one of the oil return holes. (not likely with a SBC)
You would have excessive blow by but still no water in the oil.

Anyway the place to start is with a pressure test to see how big a leak you're looking for.

If the engine has a lot of miles (more than 75000) don't just pull the heads and have the gaskets replaced.
Plan on pulling the whole engine and freshen up the bearings & rings while you're this close.
THis will mean the block has to go to the machine shop for hot tank cleaning and cam bearing install and general inspection.
You COULD bore it a little and get a new set of pistons with a little more compression . . . . . .

Get a good valve job done while the heads are off.
Forgot about those fancy 3 angle valve jobs . .they won't last on a street driven engine where you're not going to take it apart again for a few years.
Just get a stock valve job like GM did to start with.
Be SURE to have the umbrella seals on the valves replaced and be SURE they get put on the intake AND exhaust valve stems.

Get yourself a good roller timing chain & gear set.
Have your old camshaft examined by a good machinist. Tell him to look for worn lobes.
If need be, this is the time to replace the camshaft.
KEEP IT MILD for a automatic car!!

There's a few more things you'll want to replace but this is a good start.

Good luck with your engine.

 

Most likely, yes. But one of the places it could leak, is into the cylinders. It would pass out through the exhaust, without leaving a puddle on the floor. Look for white smokey exhaust. IF it is a head gasket, and IF it is leaking into a (the) cylinder(s), and enough eventially gets into a cylinder, it can cause a hydrostatic lock, which you WILL notice.

A radiator cap is probably cheaper to replace than test. You have picked a good place to start. For your sake, I hope it is also the place you can stop. Good luck.

 

this problem just started a few weeks ago. it started right after i had the crap cleaned out between the fan and condencer. my friend who did the clean out said he never saw so much crap. it filled his shop vac 1 1/2 times!!! now the car never get above 175degs. their is no white smoke (steam) comming out of the car. the car doesnt get above 175, is that warm enough for the engine to suck coolant from the over fill container? the radiator cap doesnt get warm enough to prevent touching with your hand. the car runs great.

 

CFI-EFI, you have me concerned now - I'm having similar issues with the LCL and with warm running on hotter days. I was planning on doing the big cleanout and letting that take care of it. But I read your white smokey exhaust post and got that sinking feeling. I have that issue occasionally, until the engine warms up and usually only if it hasn't been started in a week. Am I on the rebuild path?

james - sorry to jump on your question, but I figured I'd keep it in a related thread. :)

 

galvanic corosion? between Al and iron? I have heard that is common. It happened to me
:cry
The low coolant sensor sometimes goes bad. I thought I saw someone say this sensor also detects pH/acidity and signals time for a flush? :confused: Any one know 'bout that one?
My light is on frequently, but all is well.

 

Just to set the record straight. As the cooling system warms up the coolant and air in the system expand. As the pressure rises, coolant is forced past the radiator cap into the overflow tank. After the engine cools down and things start to contract, the pressure in the cooling system drops below atmospheric, and the valve in the cap allows water to be drawn from the overflow tank, back into the cooling system. This system allows for no additional air to be drawn into the engine. Without the recovery tank (resevoir), coolant would be expelled when the engine was hot and air would be drawn in when it cooled. Just like the good old days. If something, air or coolant isn't allowed back in, something has to give. Usually it is just the collapsing of a radiator hose. If the cap won't give, air could enter the system through another "open" path. Therefore, the question isn't whether 175 is warm enough to suck coolant. Unless you've taken exreme measures to keep the coolant that cool, I'd be concerned that it isn't getting any warmer. Oftimes a low coolant level will prevent consistant accurate temperature readings. Heater performance can also be spotty. I am afraid that besides the coolant having some place other than the resevoir to "vent" to, the "make up" air is coming from other than the resevoir. I suspect that is why your resevoir is always full. My reccommendation is to watch it closely after you change the cap. At any further signs of abnomality, I would have or do a pressure check on the cooling system, immediately.

PagesterL98,

Some white smoke, especially on initial fire up is normal. Keep a close eye on your coolant level. If it isn't dropping, don't worry about it. If you are losing coolant, you need to find out where it's going. A pressure check may be in your future too. Even a leaking head gasket doesn't necessarily mean an overhaul is imminant. Each case has to be decided on ot's own merits.

Good luck, guys.

 

Thanks for the info - since my levels do tend to drop faster then I would expect I'm going to head to pressure check land.

 

Have you checked that the radiator is really full? If it isn´t, you have to pack it.
:cheers:

 

ya know, im the last guy on the planet you want owning wrenches or working on your car. i took my car over to my friend/mechanic to take a look. he checked the coolant level at about 2400 rpms and said the radiator was way low. he added water at 2400 rpms,and put the cap back on. now with a little luck, that'll be the end of it. i'll let ya know.

 

Your mechanic friend did the right thing. That IS "packing" the cooling system. Now, keep a close eye on your resevoir. Check it when you park it "hot" and then again in the morning(?) before you start it, cold. The resevoir SHOULD be visibly lower, when cold. Good luck.

 

i thank God for the small things in life. after packing the radiator the problem is solved. no more coolant lite and I DONT HAVE BLOWN HEAD GASKITS!! i was prepaired to be sick :U with having to replace the head gaskits :yesnod: i feel soooo much better :p: