How to use ifelse inside the for loop in R

I have to check the names of all variables in a data.frame and if match found, need to replace the NA values in that variable with Median, else for others replace NAs with mean.

The data.frame cyl_spec has 11 variables and I have to replace NA as below:

1. Viscosity: Impute with median
2. Wax: Impute with median
3. Others: Impute with Mean

I can certainly do it by picking the variables one at a time but I was trying the following code :

attach(cyl_spec)
var <- colnames(cyl_spec)
for(val in var)
{
  if(val == 'viscosity'){viscosity[is.na(viscosity == T)] <- median(viscosity, na.rm = T)}
  else if(val == 'wax'){wax[is.na(wax == T)] <- median(wax, na.rm = T)}
  else {val[is.na(val == T)] <- mean(val, na.rm = T)}
}
detach(cyl_spec)

Somehow the code is not doing anything and I am still getting the same no of NA in the variable using this command :

sum(is.na(cyl_spec$viscosity) 

Also, when I run this code I get the following warning message :

Warning messages:
1: In mean.default(val, na.rm = T) :
  argument is not numeric or logical: returning NA
2: In mean.default(val, na.rm = T) :
  argument is not numeric or logical: returning NA
3: In mean.default(val, na.rm = T) :
  argument is not numeric or logical: returning NA
4: In mean.default(val, na.rm = T) :
  argument is not numeric or logical: returning NA
5: In mean.default(val, na.rm = T) :
  argument is not numeric or logical: returning NA
6: In mean.default(val, na.rm = T) :
  argument is not numeric or logical: returning NA
7: In mean.default(val, na.rm = T) :
  argument is not numeric or logical: returning NA
8: In mean.default(val, na.rm = T) :
  argument is not numeric or logical: returning NA
9: In mean.default(val, na.rm = T) :
  argument is not numeric or logical: returning NA

Could someone please help me with finding the solution for this, am stuck! Thanks in advance!!