Noticed Somethin Weird

[SupaMan]

My cars been doing the dreaded waterfall noise more and more lately so i took out the 3 plugs i could get too without taking the TB off (1,2 and 6) and they all looked the same not steam cleaned, i also looked down in the cly they arent steam cleaned either my oil isnt milky my coolant isnt oily car isnt over heating or running hot. but one thing i did notice was when my car is cold the over flow is just at the low mark and when its hot its about 75% to the full mark is this normal or is it the same thing a bhg does with the overflow full up but since mine is low im just not seeing it barf the coolant out?


im gonna see if i cant borrow a friends compression tester this weekend, should i do it cold or heat the car up and then do it?

 

[MA70Supra88]

Have you tried burping the cooling system of air yet?

 

[AJ'S 88NA]

^^^ What I would suggest. Then see what it does. Air traped in the system gives you the water fall noise..

 

[Silvasoup]

^^^Very true, but he should find out the cause of air in the system. Check for leaking hoses ect. In the end it is probably the dreaded BHG if there is no other cause.

 

[SupaMan]

i know what the waterfall noise is from but air in the system has to come from somewhere which is why im here asking about the compression test, and my weird overflow

i dont have any leaking hoses im tryin to find out where the air is coming from making sure its not BHG then ill burp the system im doing shit i can for free while im broke lol if you get me.

 

[SupaMan]

i just answered my own question about the compression test with the TRSM

coolant overflow question still stands.

 

[Silvasoup]

i just answered my own question about the compression test with the TRSM

coolant overflow question still stands.

From my experience some expansion in the overflow tank is normal. When I had a BHG two years ago the tank would bubble up a lot after a long run and spew out of the overflow tube. That is not a good sign. I ended up with putting in a MHG with ARP bolts and so far the problem has been solved. Almost 225K with two BHG's in the past under my belt. Waiting for the next problem to come up.:nono: One more thing I had with the BHG was steam out of the tail pipes even after a good warm up.

 

[SupaMan]

yea im not steaming at all no sweet smell nothing that a normal BHG comes with which is why im stumped about it.


so some is normal but how much is the question if its gaining like 1 litre of coolant into the tank (guesstimating the amount) that seems like alot to me.

 

[SupaMan]

thanks for the tips jet im just doin things i can do for free that might reveal it ive wanted to do a comp test on this car for a long time so itll be good to see the numbers.

main thing is i need to find out how air is getting into the system. could sitting for extended periods let air into the system?

 

[AJ'S 88NA]

thanks for the tips jet im just doin things i can do for free that might reveal it ive wanted to do a comp test on this car for a long time so itll be good to see the numbers.

main thing is i need to find out how air is getting into the system. could sitting for extended periods let air into the system?

I suppose it possible if your coolant level is low to start with.

 

[SupaMan]

yea i was thinkin that too after i saw the overflow low like maybe on first start which is where i get the waterfall it sucks up some air before coolant can cover the hose? im not completely sure i dont know exactly how the cooling system works just a lil bit.

 

[SupaMan]

Did a compression test today and these are the numbers (in psi)

1 - 155
2 - 156
3 - 155
4 - 160
5 - 155
6 - 152

i was happy with the numbers #6 is kinda low but its still in the ball park and #4 is high i dunno what causes higher compression tho.....rings sealed better than the others or somethin?

anyways i found out the waterfall noise too (i think) i put some water in the overflow enough to cover the buttom of the hose when the car is cold and when i drove it it didnt make the noise at all so hopefully it was sucking up air right when i started it then as the hose got covered it stopped. i dunno how the overflow works my impression was it didnt take anything out of the overflow until the rad got low.

anyways are those numbers good and could that have been my waterfall noise?

 

[AJ'S 88NA]

Did a compression test today and these are the numbers (in psi)

1 - 155
2 - 156
3 - 155
4 - 160
5 - 155
6 - 152

i was happy with the numbers #6 is kinda low but its still in the ball park and #4 is high i dunno what causes higher compression tho.....rings sealed better than the others or somethin?

anyways i found out the waterfall noise too (i think) i put some water in the overflow enough to cover the buttom of the hose when the car is cold and when i drove it it didnt make the noise at all so hopefully it was sucking up air right when i started it then as the hose got covered it stopped. i dunno how the overflow works my impression was it didnt take anything out of the overflow until the rad got low.

anyways are those numbers good and could that have been my waterfall noise?

Yeah the numbers are ok. The higher compression could be carbon build up for some reason in that cylinder. But over all not bad. Was the motor warm or cold for the test?

Yeah you answered your own question about the waterfall. I'd keep an eye on your coolant level to see if that was the problem...

 

[SupaMan]

Yeah the numbers are ok. The higher compression could be carbon build up for some reason in that cylinder. But over all not bad. Was the motor warm or cold for the test?

Yeah you answered your own question about the waterfall. I'd keep an eye on your coolant level to see if that was the problem...

warm i drove it for like 30 min before i started takin it apart.

yea thats the weird thing i havnt lost any coolant at all ever.

 

[xarewhyayen]

your overflow tank ?'s , The cooling system is sealed except for the overflow tank. Heating any liquid causes expansion of the liquid and in a sealed enviroment it causes a buildup of pressure. High pressure= Higher boiling point. The radiator cap's job is to hold the pressure @ .9bar or ~14psi (depending on the rating of your cap)

Any pressure in excess of that is released into the overflow tank. It can send a good bit of coolant into the overflow tank, just get worried if the overflow tank starts spilling over. As the vehicle cools off, the liquid contracts, and the rad cap allows the radiator to pull from the overflow tank as a vacuum is created to fill the space as the liquid cools. When you start your vehicle, a vacuum should not be created in your cooling system that would pull in air, its when things are cooling down.

The highest point in the supra's cooling system is the heater core, and thats where air often collects. Jack up the front end as high as possible, and let the car run for a while adding coolant as air bubbles come up. there are funnels on the market with rad cap adapters so you can put the funnel on the rad and keep it full of coolant so it fills itself as the bubbles come up.

After you bleed the system, see that you dont hear the noise, then listen for it in the future.

 

[SupaMan]

I know how to bleed the system and the fact that the heater core is the highest point.

I put coolant in the over flow and it hasnt made the noise again so i dunno what caused it but is gone.

 

[88mkIIIproject]

i've always wondered about the waterfall noise in my 7mge...

 

[iwannadie]

Drain your coolant and let it sit in container over night, if you have a nice oil sludge at the bottom. Do you notice an odd residue build up on the inside of your windshield?

Sounds alot like my bhg, also watch your oil dipstick. Make sure its pressed all the way in then check it after driving, mine would be pushed out just slightly from the exhaust leaking past the head gasket.

Mine was right around the 6cyl too, not totally blown but enough to cause small signs.

 

[CRE]

Have you tested the rad cap?

 

[iwannadie]

Have you tested the rad cap?

Or just replace it if you dont know how old it is, those things are cheap enough.