Coolant smell

[MustangS197_1995]

I'm getting a very slight coolant smell when my heater is on. Not necessarily worried. But I my first thought was the heater matrix is on its way out. No coolant in the passenger footwear or anything and you can smell it in the engine bay.

I'm hearing the pipes in the engine bay may be leaking slightly on the connectors on to the exhaust manifold then coming up through the CAF.

Are these the said pipes for the matrix? If so does anyone know the part numbers for them please? Would rather try swapping the pipes then pulling my dash out to find its fine haha

 

[Kev555]

V6? Yes that's the heater supply pipes, not sure if the same issues arise looking at your pipe layout but the heater supply pipe leaks under the inlet manifold on the 4.6. Somebody will be along later that's more familiar with your engine and the places it leaks.

 

[Dino Dino Bambino]

A common problem on the 4.0L V6 is a coolant leak from a cracked plastic thermostat housing. The cure is an aftermarket aluminium unit.

 

[MustangS197_1995]

A common problem on the 4.0L V6 is a coolant leak from a cracked plastic thermostat housing. The cure is an aftermarket aluminium unit.

Fitted a new one end of last year and aluminium one. Might take it off and reseal it

 

[TexasBlownV8]

Add a little coolant leak dye, run it, use a UV light at night to easily find the leak. If there is a serious leak, the coolant level will drop, so keep an eye on that.
The alum t-stat housing shouldn't be leaking, but if you reused all the hoses and spring-clamps, it's possible there is a seep from one of the hoses; UV light would show it.
On a family member's 4.0, one of the heater hose lines is starting to seep a little at the 90* into the firewall connection, but no smell from inside.
Smell can be coming in from the engine bay, hopefully! Changing out a heater core is NOT easy; did one once.

 

[GlassTop09]

Add a little coolant leak dye, run it, use a UV light at night to easily find the leak. If there is a serious leak, the coolant level will drop, so keep an eye on that.
The alum t-stat housing shouldn't be leaking, but if you reused all the hoses and spring-clamps, it's possible there is a seep from one of the hoses; UV light would show it.
On a family member's 4.0, one of the heater hose lines is starting to seep a little at the 90* into the firewall connection, but no smell from inside.
Smell can be coming in from the engine bay, hopefully! Changing out a heater core is NOT easy; did one once.

+1.........this.

 

[MustangS197_1995]

Update guys!
So finally worked the leak out after the dye showed no results. Leak on the heater core.

Planning on doing the evaporator core whilst I'm in there.

Bypassing it for now tomorrow until I can get all the parts together

 

[GlassTop09]

Update guys!
So finally worked the leak out after the dye showed no results. Leak on the heater core.

Planning on doing the evaporator core whilst I'm in there.

Bypassing it for now tomorrow until I can get all the parts together

Just to put this out here, that would also be a good time to replace both of those plastic heater core hose connectors w\ metal versions since you'll have these disconnected to R&R the heater core. Recently replaced all of these on my 4.6L (coolant outlet crossover under IM & both heater core inlet & return).
Dorman 800-418HP (3\4"ID x 3\4" 90* shank heater core inlet), Dorman 800-416HP (5\8"ID x 5\8" 90* shank heater core return\outlet) to cover the 2-heater core connectors.

Up to you to decide.................