Overheating suddenly today

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bayouborne

Joined
Nov 13, 2017
Threads
7
Messages
30
Location
Atlanta
Hi all - terrible day all around so far and I’m hoping for some inspired guidance here.. I’ll try to give you all the Relevant details/data but I’m typing this on my phone so..

Ok, 97 lx450, bought 6 months ago. Runs perfectly, 380k miles. No repair history came with vehicle. No idea if the head gasket has been replaced.

Drove 200 miles home today — last ten miles from home is a long grade upward. Windows were down and smelled a sweet antifreeze smell but it then went away. At this time was still running perfectly not missing not misfiring perfectly smooth. Vehicle temp normal at that time. Stopped at a friends house for 30 min and then continued home. Car immediately over heated within the first 2 miles. Signifant steam coming from under hood. Turned around and parked in friend’s driveway (4 miles total) Looked under hood immediately - found zero pressure in coolant system, upper and lower hoses completely soft and easy to pinch. No water in oil. Engine not missing, still smooth. Hoses look intact, nothing looks torn. No obvious place where the coolant was exiting.

I guess I’m looking for the next diagnostic step, or possibly a relative ranking of what’s most likely, I.e. radiator, thermostat, all smaller hose leaking near the firewall, or ... a head gasket.

Thank you for listening.. tom
 
Check your radiator cap.. if it's faulty, your radiator will boil over and overheat very quickly.
 
I'm guessing the PHH or rear heater hard lines gave out, dumping coolant.

Refill and look for leaks. Just fill with water, as yourey going to drain it for the repair amywaa.
 
BILT4ME said:
I'm guessing the PHH or rear heater hard lines gave out, dumping coolant.

Refill and look for leaks. Just fill with water, as yourey going to drain it for the repair amywaa.
Click to expand...

Yep, that’s my first step today. I’m hoping such a sudden, complete loss of coolant means a hose..
 
Moog said:
Check your radiator cap.. if it's faulty, your radiator will boil over and overheat very quickly.
Click to expand...

If you don't know the history plan on replacing the cap. It's a crucial part of the system and is cheap to replace.
 
Easiest way to look for leaks is to get a coolant pressure tester. Pump up the the pressure that your caps says and look for leaks.

I think most auto part atorst rent these too.
 
bayouborne said:
No. 1 heater bypass hose has 2” split in it. ;)

Thanks so much for all the good comments!! Tom
Click to expand...

Btw I’ve ordered the ~$15 Toyota part and it’ll take a few days to get here (this is not the little three inch one) if someone has a good procedure pls post.. I know... I should replace the little hose too.. thx tom
 
bayouborne said:
Btw I’ve ordered the ~$15 Toyota part and it’ll take a few days to get here (this is not the little three inch one) if someone has a good procedure pls post.. I know... I should replace the little hose too.. thx tom
Click to expand...
You will need a truck load of patience and few different types of pliers.
 
5/16" heater hose will work. Did one the other day, in this case used a factory hose, changing it is not all of that, just fiddly.
 
I used angled needle nose pliers when I did my last one, pull the throttle body but leave the cables on ,remove the old hose from throttle body , put new one in and route the new hose down. Then pull the old one off and stick new hose on, I used all new clamps from Toyota took bout 15 min
 
de ja vu

Zona
 
Just a post-repair followup. Here's the bad No. 1 heater bypass hose w/the 2” split in it. The rupture is at the 12 o'clock position (which makes sense, since the head's heat is continually radiating downward onto it:

20181002_122354.jpg - Shared with pCloud

I have a '97 LX450, but the ~$15 '97 Toyota replacement hose fit perfectly.

My removal experience - I have big hands and could not position tools to reach either spring clamp, from the top end (underneath the manifold) or the lower end (the side of the head). I ending up getting lucky and was able to pull on the nearest section of hose on each end and successfully pull the hose off of the fittings. The spring clamps were still on, but the hose was able to still be pulled off.

The only specialized tool that proved to be of any help was the center tool - it helped me grab the old hose and remove from the manifold fitting, as well as with new hose, slipping it onto the manifold fitting:

20181002_122529.jpg - Shared with pCloud

The other two tools were of no help to me.

For the new hose, on the top end (the manifold fitting) I used a screw-type hose clamp. I did not remove any intake manifold parts/brackets etc. I *did* spend 10 min banging together a little platform so I could relax and concentrate on the top end/manifold fitting hose removal and replacement:

20181002_123310.jpg - Shared with pCloud

That's it, it took me about 90 minutes and it wasn't particularly pleasant.

Thank you all for the thoughts and suggestions. I appreciate it.

Tom
 
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