aeroelasti

Hi, its an Rx400h 2007. I have top up my expansion tank with coolant last week as it was low, and the coolant reduced by about an inch in the expansion tank today. So I checked all the radiator hoses and connectors etc could not find any leak. But when I stick my head below the engine bay I found some pink residual at the edge of the engine oil pan. Seems to come from above the pan. I was curious!

So I went from above and start looking near the engine area, found the following:




Coolant seems to be leaking from this cover, what is this? Look like a cover to me, shaped like a thermostat but there is no thermostat. New to this engine, has it got water pump near the big pulley with no belt on? side of the engine. Was worried that it might be water pump initially but the leak seems to be from this cover. Is there a gasket or rubber ring behind this?

can’t see what is above it as I took this photo by lowering my phone into the engine bay.

thanks for any information that you can provide...

Mesquite77

This is the 3.3L, looks like freeze plug cover: https://www.clublexus.com/forums/rx-...yone-else.html

aeroelasti

Thanks, this slow leak only happened during these few weeks of cold nights, minus 4 sort of temperature nighttime, so the coolant probably freeze and push the cover out a bit causing it to leak when it slowly thaw during the day?

should I wait and see if the problem persist when the temperature warm up a bit?

still want to check my water pump, anyone knows how to check for leak without dismantling lots of stuff?

thanks.

matts6887

the water pump does have a pulley that goes around it as that is what pumps coolant from the pump through the hoses and to the radiator etc

aeroelasti

Thanks.

Is there another same cover at the rear of the engine? This is the front. Will the rear one be visible from underneath the car? Suspect the rear one won’t be too long before it leaks.

best sealant for this is it Toyota FIPG?

Margate330

Yikes!
Chilly... lol
Sending you sunshine from FL.

Felix

The w/p on the 3mz is driven by the timing belt on the passenger side. When you replace the timing belt, do the w/p as well,,,,There are a few t/b kits that include the belt, w/p as well as tensioner, idler pulleys...

matts6887

felix is right; if u do the timing belt; while yer in there and have stuff apart; ya might as well get the water pump done as well so u dont have to worry about it for quite a long time.

aeroelasti

Thanks all. Looked into the water pump area and can’t see any coolant residue. So seems ok.

I have managed to put a new freeze plug in. No more leak, has been on 2 days. But After bleeding the radiator and taking the car for a drive, the reservoir tank fall below min mark the next day. So need to top up twice. Hope this is just the car carrying on bleeding the cylinder block. I can’t find the vent plug for the cylinder block while bleeding the coolant after top up. So I did the bleeding with the old technique of raised the front of the car up, run the engine, wait for bubble to come up, did it for a good 30mins. Maybe the cylinder block still have some air pockets. But the fan did kick in and the top radiator hose is warm while I bled it.

hope the reservoir level will stay stable in the next day or two.

photos of installation


Old sealant when old plug removed

Sealant cleaned

New plug and sealant (Toyota FIPG black)

Mesquite77

Yes, there is a rather complicated coolant bleeding procedure for these cars, but even when I follow it, I end up topping it off after the first 3 or 4 trips, then it will be good for years. Be sure to run the heater full blast on your trips for a bit.

Steps from service manual to bleed coolant, key is to fill it at radiator filler neck on driver's side, be careful, that is the hot part...

1) Loosen upper drain plug
2) Put a clear vinyl tube on vent plug located on upper drain plug
3) Fill radiator at filler neck (not overflow tank) until vent tube full
4) Install radiator cap, tight
5) Fill reservoir overflow tank
6) Warm up engine and while it is running squeeze the inlet and outlet radiator hoses by hand several times
7) Stop engine and let it cool
8) Remove radiator cap and check for fluid level in radiator
9) If coolant inside radiator (not overflow tank) is not to full mark, repeat steps 1-8 until it is
10) Top off reservoir tank if needed.

Then for next 3 to 4 trips of 10min+ (turn on heater for a bit full hot), check tank when cooled off. It takes about 3 trips to stabalize.

aeroelasti

Thanks you so much for the above. And yes it took me 3 trips to get the level almost constant now. Finger crossed it will stayed.

I missed out squeezing the bottom hose. This probably would have helped as I empty the front cylinder block to the bottom to change the plug.

I changed my radiator last summer but can’t remember doing 3 trips to get it stabilise. Maybe something to do with how quickly I filled the coolant in... not sure. As long as it stays like this I am happy.

Margate330

Thank You for sharing your fix!
Awesome thread and so many great posts.

Tank

iTrader: (19)

Wow, minus 4? wonder what the OEM coolant is rated to handle...

Mika

I have same issue. One mechanic said to replace freezer plug, other said to replace radiator. But first mechanic did show me all the coolant around the plate. I already replaced radiator once at 70K... currently at 123K. Any advice what to do?

matts6887

well it shouldnt be the radiator if it was already replaced once; I would take it to a reliable 3rd opinion shop and see what they say about it cause the first 2 may not know what they are talking about. My radiator blew up on me last october.