Loosing coolant. Underhood coolant smell

[Matahoe]

I was working under the hood today and noticed my coolant reservoir was halfway empty. It was fine a month ago when I added a few quarts. It was just below the line about 1/2 inch. I also have been smelling hot coolant around my radiator shroud/ front of engine area. I don't have any leaks on the ground but it seems like I might have a leaking radiator or something. Is it normal to get a whiff of coolant around the engine bay?

 

[tom3]

Not usually. Not uncommon to have a leak that doesn't show when cold, or hot. When in the warm up stage as pressure comes up it seeps until expansion seals it. But you need to pressurize the system cold and look real hard for the spot.

 

[strutaeng]

Usual suspects are water pump, sometimes it leaks on the backside and only way to see the leak is with an inspection mirror. It could be leaking only while running.

Another common source of coolant leak is the heater hoses at the firewall, but those usually fail quickly and completely.

Radiator would be another area to look at of course.

 

[Matahoe]

Guess I can remove the radiator, block off some ports and pressure test it. It's due for a check and fin cleaning anyway. I think it's the original from 2005. I do know that the water pump was replaced about 10 years ago when the original owner had it replaced. I'll put some ultraviolet dye in the system and run it for a bit and then check. Seems like the coolant has been going down when at full temp, long distance driving...because that's the type of driving I've been doing lately over the past month.

 

[89Suburban]

A side tank on a radiator can have a small enough leak that it will not reach the ground just burn off and maybe leave some small puddling on the bottom radiator support. Need to get a light and take a good look.

 

[Matahoe]

Yeah that. I put my nose around the driver's side tank and that's where the smell is strongest. Looks like it might be time for a new radiator. But I'll check a few things before splurging. Any chance the coolant got into the oil or transmission fluid? I hope not. Thanks

 

[Marky Dissod]

You've a ship of Theseus that's about to hit its 20th anniversary.
Might be wise to consider which replacement/upgrade parts you'd like to either
have on hand in case of failure after 20 years, or
preemptively replace before failure.

I've witnessed coolant leaks so small, that a magnifying glass was needed to confirm.

 

[Matthew Jeschke]

Buy contrast dye... put it in the resiviour. Also check you engine oil of you havent already.

then use a black light. Also pressure test with radiator tester, both hot and cold... you maybe able to simply heat engine up and look without the tester once it is to pressure.

How many miles are on your truck?

 

[Scottydoggs]

you can do the free rental deal from a parts store and get a pressure tester that you leave the rad in and the system fully connected.

most common leak is the plastic side tanks on the rad. they just crack with age. its just plastic after all. thanks GM!

 

[RAMurphy]

I've had two difficult very small leaks in my coolant system to troubleshoot in the past 22 years. Both in the past 5 years. One was the radiator as described. The other was from the front steam vent crossover tube as described in this video:

Ok, I lied - I also had a water pump leak at the weep hole. But that one was quite obvious.