Passed block test, coolant boiling over

[7mgte88]

88 7mgte, T61 swap....

It was stored the winter before last, when I got it out of storage it fired up perfectly. I started on the 110ish mile trip back home with the car. Mid summer, no AC, highway driving.

Temp gauge would go 3/4 and then drop to 1/2 a few times then start climbing. Pull over, coolant is boiling out of reservoir.

Fill with 1.5ish gallons... 20 miles later, same shit.

Got it home, passed leakdown test. Pressurized cooling system, held for hours.

Car was parked until this week, started right up. Gets 1/3 on temp gauge and starts boiling coolant out.

STILL passes block tests and leakdown, cooling system still holds pressure. No oil and coolant mix at all.


I just want to confirm the damn BHG and move on to fixing it. It's my girlfriends car, she loves it more than me and wants it back on the road.


What else can I do to finally confirm the BHG?

THANKS!

 

[cmoser18]

Did you do anything to the cooling system before this started happening? Sounds like you have a lot of air in your cooling system. Try leaving the radiator cap off and running the car with the defrosters on full blast till car reaches running temps on an incline. Could also be a bad thermostat.

 

[7mgte88]

When I did the T61 swap (2 years ago now) I replaced a bunch of coolant hoses and replaced the radiator hoses with blue silicon. She daily drove the car for a couple months after that and it didn't blow coolant.

Car has done nothing but piss me off since I met her lol. Then again, if it wasn't for the car I wouldn't have met her!

 

[hvyman]

How is the radiator cap?

And t stat?

 

[IJ.]

Check for leaves and crap between the Rad and AC also any bent fins, maybe the core is blocked with garbage inside?

 

[Dan_Gyoba]

Check for leaves and crap between the Rad and AC also any bent fins, maybe the core is blocked with garbage inside?

This X2.

It's amazing how much crap can collect in there, particularly during/following storage. I've found things that I never would have believed in that space. <shudder> So worth checking out.

Also, for the price of a thermostat... Replace it. Or, cheap way to check it, put it in a pot of water, put pot on stove. Visually check that the thermostat opens before the water boils. (Don't let it rest on the bottom of the pot.) If you have a thermometer, you can check the actual temperature that it opens, but my experience is that the thermostat fails either open or closed. Both are bad.

If you want to confirm a BHG, keep driving it with coolant boiling over. Sounds like it doesn't have one now, but it will...

 

[JDMMA70]

I had this exact same issue. I have a thread with a video. My radiator was fucked. Clogged basically.

 

[7mgte88]

Radiator isn't clogged. Flushed it and it flows fine. Tstat is new. Rad cap is new.

There is nothing left of the A/C system on the car. There is also no blockage of air flow to the radiator.

Clutch fan is fine too....

 

[JDMMA70]

My radiator passed a flow test too but it was bad.....look for my old thread I tested everything you did..turned out the radiatoe was at fault and its not an uncommon issue.

 

[supraguy@aol]

I had a partially-blocked rad.
Would drive at normal temp in the summer, until i put the a/c on.
That was the system's limit with reduced flow. Apparently, the tstat was open nearly all the time to cool it, and when I added additional strain/ heat of a/c,
it revealed the problem. Went to a two-row rad, and never had a problem again.

 

[jetjock]

I love posters who say this and that is "fine" but never say how they proved it. If this one is so hell bent on thinking it's a BHG he should just go ahead and tear into it.

 

[IJ.]

Meh I tried

Getting to the point where I can't be bothered....

 

[jetjock]

The overheating/BHG thing always cracks me up. There are long established tests and procedures that will quickly resolve exactly where the problem is yet to read this forum you'd think it was diagnostic ooga-booga of the highest order.