Lower Radiator Hose Rubbing On Engine Pulley

[cleffingwell]

For the last couple of days, I have noticed that my coolant level on my 1998 LS400 with almost 160K miles has been dropping and been smelling a burning smell; like the coolant is being evaporated on the manifold or elsewhere on the hot engine. I was visually inspecting it yesterday trying to find a leak (which I haven't found yet), but noticed that the lower radiator hose was rubbing directly on the engine pulley behind it. It doesn't appear that it has worn all of the way through; which is surprising since I have owned the car nearly three years and this is the first time I've inspected that area (I'm shocked it has lasted this long). The previous owner told me he had just changed belts and hoses before selling me the car. The brand of hose is a Goodyear; does anyone know if that is an OEM or exact fit? More importantly, has anyone else experienced this with their car? I highly doubt it would have come from the factory with the hose that close to the engine pulley, so I'm guess it's either the wrong hose or a poorly made aftermarket fit. Anyway, I plan on taking the car into a local and reputable independent Lexus shop (Davenport's in Plano, Texas) to have them diagnose the leak and burning smell. I will of course have them change out the hose for a new one. Also, I noticed that there is green coolant in the reservoir, so I'll ask them to flush and replace it with the Toyota Red and distilled water 50/50 mixture.

One of my suspicions (and I assume is a worst-case scenario) is that I have a blown head gasket and that is the source of my coolant leak. Any thoughts come to mind?

[SRK]

Sounds to me like you are doing the right things. Changing the hose to a factory one is great - it will fit correctly. Changing the coolant back to Toyota red is good.

If you are smelling coolant then it's exiting the engine. Blown head gaskets are rare - I've never heard of one on the V-8's. Other cars all time of course. When coolant is burned and goes through the converters it gets a nasty and different odour.

It is probably a slow leak at the water pump, and in many cases it's not visible as the coolant evaporates before it can get low enough to be seen. The covers hide the leak. My LS smelled without dropping coolant on the ground. So I'd suspect the water pump.

And welcome to the site!

[cleffingwell]

Quick update on this: earlier today, I removed the plastic cover under the engine to get a better view of the affected area from underneath. After a long time of close inspection with a bright flashlight, I'm nearly convinced that the coolant leak is coming from the hose that is rubbing on the engine pulley. Although you can't see it visibly leaking when the motor is running; ALL of the fluid and debris seems to be centered around that spot. The rest of the engine bay looks really good. So, I guess the radiator fluid is coming out under pressure as a fine mist, then burning when it makes contact with the hot engine. So, I'm going to just change out this hose myself and see if that fixes the problem. I'm also going to flush the system with water (at least once), and switch over to the Toyota Red and distilled water 50/50 mixture (and DAMN, that Toyota Red is expensive at $30 per gallon!). What is still a mystery to me is why the hose pushed up against the pulley in the first place. Like I wrote earlier, I have owned the car nearly three years and this area has never been touched in that amount of time. The previous owner told me he had changed all the belts and hoses before I bought it. Obviously, this is an aftermarket hose; but even with that, how could it go three full years without touching that pulley (or even more unbelievable, rubbing against it for three years). I double-checked that the hosed is fully seated at the mount points where it is attached; both top and bottom. So, why would it all of a sudden flex out into that pulley? The rubber doesn't look stressed or distorted; but rather, still looks fresh and correct. I guess it won't really matter once I switch it out.

Quick question: will I be able to add the new coolant in without removing and replacing the thermostat? Most of the tutorials I see online involve replacing the thermostat and O-ring, but mine seem to be fine; so I wasn't planning on it. However, I bought the car with 112K and it now has almost 160K miles; so maybe it needs to be replaced anyway after 40K+ miles?

Full Disclosure: I'm actually going to try an aftermarket hose first. The one from the Lexus stealership was $53, and the one from AutoZone is $19.99; so I'll at least see how well it fits. I can always take it back and have the dealership order me an OEM one.

[cleffingwell]

I should have more correctly written that I'm nearly convinced the coolant was/is leaking ONLY from the hose rubbing against the pulley. I know that seems kind of "Duh!" on the surface, but it's important to me to rule out any other possible leaks. Considering how good the rest of the engine, hoses, etc. looks; I think this is the only leak. Also, ever since I put some of that temporary host patching tape on it yesterday; the coolant level seems to be holding steady. This gives me some good mental comfort that it may simply be that hose and nothing else (much less the dreaded blown head gasket). I should be able to change out the hose and coolant tomorrow, so hopefully I can get a resolution posted later tomorrow or this week.

[SRK]

The coolant price isn't too bad, if it's the undiluted part number. Toyota does sell the stuff already diluted to 50/50 and the price should be lower for that.

The hoses aren't cheap, but they are far better quality than anything made by NA companies. My 1992 LS (sold to a friend) has all the original hoses - after 22 years!

There is a bleed screw on the top of the thermostat housings as I recall, should be one on yours. No need to disturb the thermostat itself, but be sure to bleed the air out of the system when you refill it. Flush until all the green is gone- the red Toyota coolant is not compatible.

The only reason I can think that the hose "suddenly" begins touching is a broken or soft engine or trans mount allowing the engine to change position re the radiator.

Hopefully it's just the hose and you'll have Lexus reliability again!

[landar]

Personally, I would stay the heck away from Autozone hoses. Particularly the Duralast stuff. I would spring for the Toyota OEM but even NAPA has better hoses than AZ.

Why your hose would shift position is a mystery unless it was always off position. You can loosen a connector and twist the hose end slightly to gain more clearance. But if it is already messed up, it must be replaced.

You burp the LS by simply letting the engine warm up and, with the heater on hi heat, rev to 2-3k RPMS for a few minutes. The air will find its way out.

[cleffingwell]

Well, I changed out the lower radiator hose today, using the AutoZone hose (at least for now); but I did trim almost an inch off the lower mount end (the radiator end) to keep it further away from the engine pulley. I also flushed the system well with distilled water, then replaced with the 50/50 mixture of Toyota Red and distilled water; it took a little over two gallons of mixture (approximately 2.5). I went slowly and deliberately, and it seemed to go well overall. I'll keep an eye on the coolant level over the next week or so to know if I am still losing coolant or not.

However, during the job today, I discovered something that is quite disturbing. I noticed that both sides of the engine are seeping an oily substance at where (I think) is the head gasket. It is worse on the passenger side; where the oil is leaking down onto the exhaust manifold and that is what is causing the burning smell. There is also a leak on the driver's side, but doesn't seem nearly as bad. From what I read on several other posts on this forum, blown headgaskets on these motors are very rare; and my car does NOT have any of the symptoms that are typically described (such as white smoke, cloudy oil, overheating, etc.)...none at all so far. So, can there be an engine oil leak in that same area without it being the head gasket? Do these engines have valve cover gaskets similar to American V-8's? I can get a pretty decent look at it and see where the oil is coming from; just not 100% sure what I'm looking at. It's definitely a noticeable issue though. BTW, how much does it usually cost to have these gaskets replaced at a good independent shop; and is it worth doing?

[SRK]

Sounds like cam cover gaskets, not head gaskets. If the oil is just a seep, and not reaching the ground, don't worry about it. You might try gently tightening the bolts (nuts?) holding the covers on.

If the oil is getting to the exhaust manifolds, then it's above that level, and that means cam covers.

[cleffingwell]

Thanks much for the info! That sounds a little more positive than the head gaskets, so I will try gently tightening the bolts/nuts holding the covers on. Do you happen to know the torque specs, or where I can find them (or if it really matters)?

The oil isn't reaching the ground, but it is going down the manifold; and some is even going down the exhaust pipe to the frame/crossmember area and that plastic undercover. I wiped up much of it today when I had the undercovers removed, so I'll keep an eye on how much of it reappears.

[cleffingwell]

Just to clarify, this is the part of the engine where the wires connect with the spark plugs. Is that indicative of the cam covers?

Thanks,

Clint

[cleffingwell]

Ok, after the tip from SRK above, I have determined it is almost definitely the cam cover gaskets. I reviewed several other discussion threads about replacing the cam cover gaskets. It looks like a pretty involved job; but not impossible. There were also several recommendations to try tightening the bolts first; but be very careful, because the torque specs are only 53 inch-pounds. My torque wrench only dials down to 120 inch-pounds, so I'll either have to get another one or just use the socket on an extension and do it "finger tight". Also, I can only reach about 2 or 3 of the bolts with my straight socket extension, so I'll have to also pick up a universal extension to flex at the right angle. However, the few bolts I could reach were as "loose as a goose"; so fingers crossed that a simple tightening to spec will do the trick! :-)

[SRK]

Fifty three inch pounds is not much more than "screwdriver" tight. I don't use, and have never used, torque wrenches on such low values, or such non-critical parts. Just tighten firmly. You'll be fine.

Don't be in a hurry to replace the gaskets. They've simply loosened, and I'll bet that solves the problem.

[cleffingwell]

Well, I picked up a universal joint socket extension this morning and snugged up the cam cover bolts. Nearly every one was VERY loose. I'm pretty confident it will go a long way in stopping the oil seapage. I still need to clean up the engine to spot any future leakage, but at least the burning smell seems to have gone away (which I assume means it is not leaking down onto the exhaust manifold anymore). I'll know more as I monitor it over the next week or two. I'm going to do a separate post asking for recommendations on properly cleaning the engine and engine compartment.

Also, the coolant level seems to be holding steady; so the hose replacement seems to have worked like a champ. Thanks so much for all the advice!

[SRK]

I'm glad it's all worked out Clint. Good job fixing it.

As to cleaning, I just use solvent on a rag and wipe things down that are oily. For the general engine compartment a damp towel to get the dust off. With all of the electrical connections it's not worth spraying water anywhere. And as you have seen Lexus has sealed the engine compartment against water quite well.

Anytime I remove a plastic shroud or panel or component, I'll hose it down in the driveway and dry and re-install it. But I don't spray a hose anywhere near the engine.

[Jollyczar]

I recently changed my valve cover gaskets and had never done them before. I don't know what a shop or the dealership would charge but it is VERY doable if you have some basic mechanic skills. My old gaskets were rock hard and almost useless as seals which led to the same leaks you describe. I say tighten them down and check them regularly while you read up on the posted write ups and change them out when you are ready. I will help out with any questions as will many others here I'm sure. I took a bunch of pics on my 2000 ls400 and have the FSM to share also.

[jimjim2331]

.....I am new to forum and don't have hang of it yet, you are right to have repair you mention. I have a small issue I need help on. Brought my LS350 (2009) to have recall replace on the cam gears. First thing I look under hood to see any obvious problem. On right front inside fender well there is an AC hose anchor bracket. In the bracket there is an appropriate hole to connect AC hose. About one and half inch under bracket there is AC hose with appropriate fitting to go into the hole above in bracket. At first glance it looks like they forgot to connect AC hose to anchor bracket. I bring to their attention and they say everything OK and hose not designed to be attached to bracket. Don't make sense to me. Anyone out there with 350 would you look at your car and tell me if hose belongs attached to bracket. Thanks JimB