1G Coolant issues

[I21chardh]

Hello all. I recently got my car back on the road with a new engine and I’m still experiencing some cooling issues.

I initially had overheating which would trigger the CEL. I put a higher capacity fan in which has got the car to now not overheat to the point of triggering CEL but I feel like coolant is still getting too hot as it is entering coolant overflow boiling after some highway pulls and not completely returning to full level within tstat housing once it cools off.

I feel like this may not be an air flow issue but possibly something else. I am losing about a quart of coolant ever 50 or so miles it seems with no obvious leaks. Only coolant on ground is coming from overflow tank tube. I’ve tried a few different caps and raising the coolant overflow tank up about 2 inches but did not resolve the problem.

Currently running generic antifreeze/coolant premix. What should be my next move? Thanks in advance!

 

[pauleyman]

What thermostat is in the car, what radiator. What are current coolant temps? Did you check that generic coolant for concentration?

 

[I21chardh]

Stocks tstat, mishimoto, I’d have to check log to get exact temps. I have not checked coolant.

 

[pauleyman]

Stocks tstat, mishimoto, I’d have to check log to get exact temps. I have not checked coolant.

stock as in OEM or a stock equivalent? What temp? 180? 195?

 

[I21chardh]

OEM. I believe 195

 

[We're on Boost]

One thing to check is, look for cracks in the underside of the exhaust manifold.
Check out this post #52 by @TSIdad

https://www.dsmtuners.com/threads/overheating-issue.540996/page-3#post-153893789

 

[I21chardh]

After logging it stays around 200F driving around town.

 

[curt-s]

That's a good temp. If the coolant was getting too hot, you'd be going well above 200. Something else may be pressurizing the system, forcing the cap to release into your overflow.

At this point I'd be testing a few things just to see if there's a threshold at play:

How much coolant do you lose puttering like an old man around town

How much coolant do you lose with the wastegate open (no boost allowed) and getting on it, such as that is with no positive pressure

How much coolant do you lose at 5, 10, 15, 20psi (you may have to swap wg springs to hit the low ones)

Granted all of these will increase your temps, but it's more of.. which happens faster? Do you lose more coolant in high boost before the temps get up there
Just a test.

 

[CrackedDSM]

The OEM fans won’t even kick on unless coolant temp is like 203-207*. The thermal switch is on the bottom of the radiator and that’s what triggers the fans on or off.

If you have ECMLink or want to be ghetto and wire them up to a toggle switch you can get them to come on sooner but honestly, unless it’s touching 210+ I wouldn’t even sweat it.

 

[We're on Boost]

Your stock type thermostat is not even fully open yet at 200 F.
According to the 1g FSM I have (1991) the stock thermostat starts to open at 190 F and becomes completely open at about 212 F.

 

[curt-s]

You have two temp senders, three counting the fan switch, so if they agree you can rule out the ecu one as bad.
So your overflow tank is 100% full causing excess is draining to ground?

If you idle without the cap are you getting bubbles?

You might need extreme combustion pressure (like when under a good amount of boost) to push that gas into your coolant. Ie. A failed head gasket. I'm not willing to say that is in fact the issue yet though

 

[We're on Boost]

Maybe you could tell us a little more about your engine build.
In your build thread you say "Dropping in a freshly built long block complete with o ring deck".
But the pic you show is a short block.
In your specs you mention English Racing.
Did they build the short block and are they the ones who got the o-ring grooves done?
Who built the head, and who assembled the head to the block?
Who checked the head for cracks and pinholes before putting it together?
The car looks nice BTW. Really would like to see this working well.