Coolant loss, got it!

Toyotafanboi

Sorry, new thread. Think the old one is too messy.

Ok, done a mega drive today (went just over 100 miles), checked the car after i parked up and found this. Now that i look at it, you can also really see the white chalky build up along the casting line on the intake manifold. It's being spat out through the overflow pipe on the resevoir. given i have a new pressure cap on the resevoir, is the only other likely outcome a leak through the head gasket from the combustion chamber through to a coolant gallery?

For what it's worth, i tracked the temperature via obd for the whole drive and while on the move it was a steady between 79-81 degrees celcius and got as high as 87 degrees celcius once when at a standstill.

Tony Beetroot

Immerse the overflow pipe into a clear bottle of water making sure its under the water. Run the engine and look for bubbles coming from the tube. A few is normal as long as they clear. A steady stream of bubbles indicate compression gasses leaking into the cooling system, ie head gasket and or cracked head.

whizbang

Have you a rubber pipe fitted inside the cap of the reservoir ?
-make sure its on the inlet side.

Maybe there's an old lump of radweld bumbling around inside the system, and every now and again, it blocks the flow..

nd

Is there any sign of oil or fuel in the new coolant?

Toyotafanboi

No, the new coolant still looks a good colour but there is only around 250 miles on it. I'm going to try Tony Beetroots suggestion above later on today.

Alanstrainor

Hopefully I'm not just confusing things here...but are you fairly certain the cooling system is properly bled? I just remember how much of a pain it was with mine to get right...

Special Circumstances

Pending confirmation from a pro... but is that low for a normal operating temp?
I was around that temp with a rad in the early stages of leaking at the plastic/alloy junction, so the system wasn't pressurising properly.
Pretty sure I'm back to hovering above 90 now.

I would have thought you'd see the coolant reservoir almost full to the top when you stopped if was pushing it out the overflow. I'm used to non pressurised expansion tanks though.

Toyotafanboi

OK, so using the method above, no bubbles at all, checked from cold start until it got up to temperature.

I am assuming i done a good job bleeding it based on the fact that toyota says it takes "approx" 4.5 liters of coolant and i got that much back in while refilling, but the manual only offering an approximate value isn't very comforting. Would excess air in the system give me this kind of problem? These cars are a notorious bitch to bleed though as the rad and resevoir are so much lower than the engine because of the shape of the nose.

Intetesting thoughts SC, i did think 80 was a tad low. The thermostat i fitted said 82 degrees celcius on it which could have some sort of implication. If the rad was gone and the system wasn't pressurising enough to get up to temp, how would i have enough pressure in the expansion tank to cause that spitting?

I'm tempted to change the rad as my next step as they are a well known weak spot on these cars, i'm only hesitant as it does look in ok condition and they are like €200.

Sorry for all the questioning but it is the DIY forum

nd

Is it still spitting? I presume the overflow pipe is there in case there is excess coolant. Maybe it just spat a bit after you changed the coolant until it found it's natural level.

Is the coolant level between the min and max mark when it's cold?

Alanstrainor

I know when I didn't have my BMW bled right, I had a good bit of pressure released through the cap. Mine wasn't overfilled, simply not bled with air pockets. I do fear that I shouldn't be giving advice here given the massive difference between cars.

Tony Beetroot

Toyotafanboi wrote: »

Intetesting thoughts SC, i did think 80 was a tad low. The thermostat i fitted said 82 degrees celcius on it which could have some sort of implication. If the rad was gone and the system wasn't pressurising enough to get up to temp, how would i have enough pressure in the expansion tank to cause that spitting?

That temperature is fine, if your rad was gone you would see it leaking and be loosing coolant. I don't fully get you with this spitting term, as another poster said what are the levels like?

dooroy

The figure stamped on the thermostat is the opening temp - coolant has to reach this before it opens .
The pressure in the system does not 'bring up the temp'.
The idea of a pressurized system is that the temp of the coolant can go above 100 C without boiling . This is why it can be dangerous to remove the rad cap from a hot engine - the release of pressure can allow the coolant to boil suddenly.
The radiator cap is designed with a valve that will open if the pressure goes above a certain value - as caps get older this valve may weaken and open too early allowing coolant to escape even though there is nothing 'wrong' as it were.
If there are pockets of air in the system they can expand quickly on reaching a certain temp and force out coolant - giving the impression that the car is overheating/boiling etc .

jca

Simple question, is the coolant level dropping or not since you've replaced the thermostat and cap? I think you're over analysing the whole situation.

Toyotafanboi

initially when i was refilling the coolant after bleeding i refilled it to max on the resevoir. After the a short drive, (10 miles) it worked its way back to minimum on the resevoir (checked when cold), so i topped it back up to max on the resevoir.

This time it's taken more like 150 miles and it's nearly back at minimum in the resevoir (when cold).

To elaborate on "spitting". When i pulled in with a hot engine, i went to check the level after a minute or two after i parked with the engine off. I didn't open the resevoir, i just looked at it and as i looked at it, it was like the resevoir sneezed. It made a squirting sound and a trickle of coolant came out, all over and done with in a split second.

Tl;dr. Coolant has traveled from max to min twice now, but took a lot longer the second time.

nd

I wouldn't worry about it being on the low side when cold.

I'd try not topping it up, and keep a close eye on it. If it keeps dropping below min then there's def. a problem.

The Muppet

Id fill it to max again and see if you continue to lose coolant. It could just be pockets of air being expelled as you drive.

nd

When I was trying to make sure I'd all the air out of my car after changing the coolant, I read you should take it for a drive/rev it above about 3-4k rpm for a sustained period, as this will make sure the water pump pumps the water around fast enough to force out any pockets of air.

jca

nd wrote: »

When I was trying to make sure I'd all the air out of my car after changing the coolant, I read you should take it for a drive/rev it above about 3-4k rpm for a sustained period, as this will make sure the water pump pumps the water around fast enough to force out any pockets of air.

I wouldn't take it to that extreme as a car water pump can shift a surprising amount of water at what seems like low rpm.

Toyotafanboi

In what may be a logical situation, the car was right on 'low' this morning, took it for a good spin and when the engine is up to temp it is right on 'max' on the resevoir.

If it doesn't drop below low when cold, i could be winning.

Alanstrainor

Does the manual state to check the coolant level when cold? I would presume it does? If so, top it up when cold too. Checking when cold, driving, and checking when hot may not be the best approach.

Tony Beetroot

It should be at max when cold, top it up to max next time its cold, ignore any warm readings.

dooroy

Check the handbook /manual as some cars are OK to be at min when cold and max when hot.
The rise in level is caused by expansion - and if you fill them to max when cold some coolant may be pushed out when hot .

Toyotafanboi

So, pretty sure it's the head gasket leaking through to the outside of the block. Going to strip the car back a bit as it's very close to the top rad hose so i might get lucky and have a damaged hose etc (unlikely).

Found this damp patch on the back corner of the block.


Touched it with a trusty macky d's napkin, definitely coolant.

nd

Toyotafanboi

Yeah, sick. Best built cars in the world my arse.

knickerbocker

Dude, I feel your pain........ My Mitsubishi Pajero sport is in need of a new head gasket, and hopefully there's not a crack in the head, though I shouldn't complain really with 240k miles on the clock. Worst part is I'll have to rent a van for a week while I strip it down

nd

I suppose there'd be nothing to loose on retorquing the head bolts.

jca

nd wrote: »

I suppose there'd be nothing to loose on retorquing the head bolts.

Or lob in a can of Radweld... I'm going to be eaten alive for suggesting it but at this stage I'd give it a try.

Toyotafanboi

jca wrote: »

Or lob in a can of Radweld... I'm going to be eaten alive for suggesting it but at this stage I'd give it a try.

Honestly i was thinking the same. I very nearly done it too. But then i remembered all those horror stories of it blocking heater matrix' etc and given how hard the celica is to bleed properly i could just see it leading to a whole other world of pain for me.

Like i posted in the chat thread, i have arranged for a second hand engine, supplied and fitted for €600. I'm keeping my old engine too so i can repair it in my own time and learn a bit too and then i'l also have a backup engine in future. Full dgt mode :pac: